На домашнем стоит ru. Не  обращаю даже внимание.
Дети сидят и всем довольны.

# Mozilla User Preferences

/* Do not edit this file.
*
* If you make changes to this file while the application is running,
* the changes will be overwritten when the application exits.
*
* To make a manual change to preferences, you can visit the URL about:config
*/

user_pref("accessibility.typeaheadfind.flashBar", 0);
user_pref("app.update.auto", false);
user_pref("app.update.enabled", false);
user_pref("app.update.lastUpdateTime.addon-background-update-timer", 1339490852);
user_pref("app.update.lastUpdateTime.background-update-timer", 1339505770);
user_pref("app.update.lastUpdateTime.blocklist-background-update-timer", 1339490972);
user_pref("app.update.lastUpdateTime.search-engine-update-timer", 1339490731);
user_pref("app.update.service.prefetchCleared", true);
user_pref("breakpad.reportURL", "127.0.0.1");
user_pref("browser.bookmarks.restore_default_bookmarks", false);
user_pref("browser.cache.check_doc_frequency", 1);
user_pref("browser.cache.disk.capacity", 1048576);
user_pref("browser.cache.disk.smart_size.first_run", false);
user_pref("browser.cache.disk.smart_size_cached_value", 819200);
user_pref("browser.cache.memory.capacity", 524288);
user_pref("browser.contentHandlers.types.6.title", "Sage");
user_pref("browser.contentHandlers.types.6.type", "application/vnd.mozilla.maybe.feed");
user_pref("browser.contentHandlers.types.6.uri", "chrome://sage/content/feedsummary.html?uri=%s");
user_pref("browser.download.lastDir", "C:\\Users\\Mah\\Desktop");
user_pref("browser.download.manager.alertOnEXEOpen", true);
user_pref("browser.download.manager.scanWhenDone", false);
user_pref("browser.download.manager.showAlertOnComplete", false);
user_pref("browser.download.manager.showWhenStarting", false);
user_pref("browser.download.useDownloadDir", false);
user_pref("browser.feeds.showFirstRunUI", false);
user_pref("browser.migration.version", 6);
user_pref("browser.places.smartBookmarksVersion", 4);
user_pref("browser.preferences.advanced.selectedTabIndex", 0);
user_pref("browser.rights.3.shown", true);
user_pref("browser.safebrowsing.enabled", false);
user_pref("browser.safebrowsing.malware.enabled", false);
user_pref("browser.safebrowsing.malware.reportURL", "rty");
user_pref("browser.safebrowsing.provider.0.gethashURL", "try");
user_pref("browser.safebrowsing.provider.0.reportURL", "df");
user_pref("browser.safebrowsing.provider.0.updateURL", "try");
user_pref("browser.search.openintab", true);
user_pref("browser.search.selectedEngine", "Google Web  (ua)");
user_pref("browser.search.update", false);
user_pref("browser.search.useDBForOrder", true);
user_pref("browser.sesionhistory.max_entries", 5);
user_pref("browser.sessionhistory.max_entries", 5);
user_pref("browser.sessionstore.interval", 300000);
user_pref("browser.shell.checkDefaultBrowser", false);
user_pref("browser.startup.homepage", "https://www.google.com.ua/webhp?hl=ru&tab=ww");
user_pref("browser.startup.homepage_override.buildID", "20120608081921");
user_pref("browser.startup.homepage_override.mstone", "16.0a1");
user_pref("browser.startup.page", 3);
user_pref("browser.syncPromoViewsLeft", 0);
user_pref("browser.tabs.animate", false);
user_pref("browser.tabs.closeWindowWithLastTab", false);
user_pref("browser.taskbar.lastgroupid", " A3710B8EBB50CD3");
user_pref("called content.interrupt.parsing", false);
user_pref("config.trim_on_minimize", true);
user_pref("content.notify.backoffcount", 5);
user_pref("content.notify.interval", "250000");
user_pref("content.notify.ontimer", true);
user_pref("content.switch.threshold", "25000");
user_pref("devtools.inspector.sidebarOpen", true);
user_pref("dom.disable_window_open_feature.resizable", false);
user_pref("dom.storage.enabled", false);
user_pref("dwhelper.conv-conf.auto.bc1e2619f37bea59f347c7c0c775df02", true);
user_pref("dwhelper.convert-free", true);
user_pref("dwhelper.first-time", false);
user_pref("dwhelper.icon-animation", false);
user_pref("dwhelper.last-media-host-blacklist", "pop6.com|redlightcenter.com|dtiserv.com|mp3tunes.com|netflix.com");
user_pref("dwhelper.last-shared-blacklist", "1338239650948");
user_pref("dwhelper.last-version", "4.9.9");
user_pref("dwhelper.menu-expiration", 60);
user_pref("dwhelper.passwords-migrated", true);
user_pref("dwhelper.safe-mode", false);
user_pref("dwhelper.smartnamer.last-shared", 1338239676);
user_pref("extensions.PlacesCleaner.hidestatus", false);
user_pref("extensions.PlacesCleaner.lastvacuumtime", "1339073638527");
user_pref("extensions.PlacesCleaner.preserveday", 7);
user_pref("extensions.adblockplus.currentVersion", "2.0.3");
user_pref("extensions.blocklist.pingCountTotal", 49);
user_pref("extensions.blocklist.pingCountVersion", 3);
user_pref("extensions.bootstrappedAddons", "{\"elemhidehelper@adblockplus.org\":{\"version\":\"1.2.2\",\"type\":\"extension\",\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\elemhidehelper@adblockplus.org.xpi\"}}");
user_pref("extensions.databaseSchema", 13);
user_pref("extensions.enabledAddons", "secureLogin@blueimp.net:0.9.9,translator@zoli.bod:2.1.0.1,{02450914-cdd9-410f-b1da-db004e18c671}:0.96.5c,{a6ca9b3b-5e52-4f47-85d8-cca35bb57596}:1.4.12,{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}:2.0.3,fastdial@telega.phpnet.us:4.2.2,Restart@schuzak.jp:0.0.0.5m,PlacesCleaner@sto.tw:0.41,artur.dubovoy@gmail.com:3.6.2,langpack-ru@firefox.mozilla.org:16.0a1,{972ce4c6-7e08-4474-a285-3208198ce6fd}:16.0a1");
user_pref("extensions.fastdial.options", "{\"width\":\"3\",\"height\":\"4\",\"thumbWidth\":\"300\",\"fixed\":false,\"hideEmpty\":true,\"hideBack\":false,\"openIn\":\"\",\"shortcutKey\":\"\",\"timeout\":\"1000\"}");
user_pref("extensions.fastdial.root", 145);
user_pref("extensions.fastdial.search", "[]");
user_pref("extensions.fastdial.sort", "visits");
user_pref("extensions.fastdial.theme", "~");
user_pref("extensions.fastdial.version", "2.23b3");
user_pref("extensions.googletranslatorforff.firstrun", false);
user_pref("extensions.googletranslatorforff.targetlang", "ru");
user_pref("extensions.googletranslatorforff.toolbarbuttonplaced", true);
user_pref("extensions.googletranslatorforff.version", "2.1");
user_pref("extensions.installCache", "[{\"name\":\"app-global\",\"addons\":{\"{972ce4c6-7e08-4474-a285-3208198ce6fd}\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\Desktop\\\\FirefoxPortableTest\\\\App\\\\Firefox\\\\extensions\\\\{972ce4c6-7e08-4474-a285-3208198ce6fd}\",\"mtime\":1339462174326}}},{\"name\":\"winreg-app-user\",\"addons\":{\"{3ED591BC-7CC7-495B-A526-B2431356EDC1}\":{\"descriptor\":\"C:\\\\Program Files\\\\Ad Muncher\\\\FirefoxExtension_2.0\",\"mtime\":1335827999300}}},{\"name\":\"app-profile\",\"addons\":{\"artur.dubovoy@gmail.com\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\artur.dubovoy@gmail.com.xpi\",\"mtime\":1339423809052},\"elemhidehelper@adblockplus.org\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\elemhidehelper@adblockplus.org.xpi\",\"mtime\":1334723002064},\"fastdial@telega.phpnet.us\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\fastdial@telega.phpnet.us\",\"mtime\":1338566015194},\"langpack-ru@firefox.mozilla.org\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\langpack-ru@firefox.mozilla.org.xpi\",\"mtime\":1339463633357},\"PlacesCleaner@sto.tw\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\PlacesCleaner@sto.tw.xpi\",\"mtime\":1339073463579},\"Restart@schuzak.jp\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\Restart@schuzak.jp.xpi\",\"mtime\":1338835951488},\"secureLogin@blueimp.net\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\secureLogin@blueimp.net.xpi\",\"mtime\":1334635159026},\"translator@zoli.bod\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\translator@zoli.bod.xpi\",\"mtime\":1338239499296},\"{02450914-cdd9-410f-b1da-db004e18c671}\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\{02450914-cdd9-410f-b1da-db004e18c671}.xpi\",\"mtime\":1334635159033},\"{25A1388B-6B18-46c3-BEBA-A81915D0DE8F}\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\{25A1388B-6B18-46c3-BEBA-A81915D0DE8F}.xpi\",\"mtime\":1338835744788},\"{a6ca9b3b-5e52-4f47-85d8-cca35bb57596}\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\{a6ca9b3b-5e52-4f47-85d8-cca35bb57596}.xpi\",\"mtime\":1338240602389},\"{ada4b710-8346-4b82-8199-5de2b400a6ae}\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\{ada4b710-8346-4b82-8199-5de2b400a6ae}\",\"mtime\":1339463565320},\"{b9db16a4-6edc-47ec-a1f4-b86292ed211d}\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\{b9db16a4-6edc-47ec-a1f4-b86292ed211d}\",\"mtime\":1338239649224},\"{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}\":{\"descriptor\":\"C:\\\\Users\\\\Mah\\\\AppData\\\\Roaming\\\\Mozilla\\\\Firefox\\\\Profiles\\\\4jp74pwn.default\\\\extensions\\\\{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}.xpi\",\"mtime\":1334046493450}}}]");
user_pref("extensions.lastAppVersion", "16.0a1");
user_pref("extensions.lastPlatformVersion", "16.0a1");
user_pref("extensions.pendingOperations", false);
user_pref("extensions.qls.autoswitchhosts", " addons.mozilla.org;ru-RU");
user_pref("extensions.qls.backup_acceptlanguages", "ru-RU,ru,en-US,en,de-DE,de");
user_pref("extensions.qls.contentlocale", "en-US");
user_pref("extensions.qls.fallbacklocale", "en-US");
user_pref("extensions.qls.locale", "en-US");
user_pref("extensions.qls.previouscontentlocale", "ru-RU");
user_pref("extensions.qls.previouslocale", "en-US");
user_pref("extensions.qls.switch_accept_languages", false);
user_pref("extensions.qls.switch_alwaysask", true);
user_pref("extensions.qls.switch_gulocale", true);
user_pref("extensions.reminderFox.categories", "Anniversary,Birthday,Business,Customer,Follow Up,Holiday,Miscellaneous,Personal,Projects,Vacation");
user_pref("extensions.reminderFox.lastAlert", "1339463724010");
user_pref("extensions.reminderFox.lastModified", "1339463568168");
user_pref("extensions.reminderFox.lastProcessed", "1339463718017");
user_pref("extensions.reminderFox.migrated", "1.9.9.5.1");
user_pref("extensions.reminderFox.views", "Upcoming Birthdays=<Summary:Birthday;DATE:1M;>,Holidays=<CATEGORIES:Holiday;>,Mailed reminders=<SUMMARY:Mail,Send;DATE:-6M,4W;>,All Reminders (all years)=<DATE:-99Y,99Y;>,");
user_pref("extensions.sage.version", "1.4.12");
user_pref("extensions.secureLogin@blueimp.net.hideToolbarButton", true);
user_pref("extensions.secureLogin@blueimp.net.searchLoginsOnload", true);
user_pref("extensions.shownSelectionUI", true);
user_pref("extensions.ui.dictionary.hidden", true);
user_pref("extensions.ui.lastCategory", "addons://list/extension");
user_pref("extensions.ui.locale.hidden", false);
user_pref("font.default.x-cyrillic", "sans-serif");
user_pref("font.name.monospace.x-cyrillic", "Droid Sans Mono");
user_pref("font.name.sans-serif.x-cyrillic", "Droid Sans");
user_pref("fvd_single.download.custom", true);
user_pref("fvd_single.download.folder", "F:");
user_pref("fvd_single.fvdsd_last_used_version", "3.6.2");
user_pref("fvd_single.in_new_tab", false);
user_pref("fvd_single.is_first_run", false);
user_pref("fvd_single.single.dont_display_features_hint", true);
user_pref("fvd_single.supported_sites.check_interval", "2333080296");
user_pref("fvd_single.supported_sites.last_check", "Mon, 28 May 2012 21:20:49 GMT");
user_pref("general.useragent.locale", "ru");
user_pref("general.warnOnAboutConfig", false);
user_pref("geo.enabled", false);
user_pref("geo.wifi.uri", "127.0.0.1");
user_pref("gfx.direct2d.disabled", true);
user_pref("gfx.use_text_smoothing_setting", true);
user_pref("greasemonkey.haveInsertedToolbarbutton", true);
user_pref("greasemonkey.version", "0.9.18");
user_pref("html5.enabled", true);
user_pref("idle.lastDailyNotification", 1339419339);
user_pref("intl.accept_languages", "en-US,en,ru-RU,ru,de-DE,de");
user_pref("intl.charsetmenu.browser.cache", "windows-1252, UTF-8, ISO-8859-1, KOI8-R, windows-1251");
user_pref("keyword.URL", "Google Web  (ua)");
user_pref("keyword.enabled", false);
user_pref("network.cookie.cookieBehavior", 1);
user_pref("network.cookie.prefsMigrated", true);
user_pref("network.http.connect.timeout", "60");
user_pref("network.http.max-connections", 48);
user_pref("network.http.max-connections-per-server", 16);
user_pref("network.http.max-persistent-connections-per-proxy", 12);
user_pref("network.http.max-persistent-connections-per-server", 8);
user_pref("network.http.pipelining", true);
user_pref("network.http.pipelining.firstrequest", true);
user_pref("network.http.pipelining.maxrequests", 24);
user_pref("network.http.proxy.pipelining", true);
user_pref("network.http.redirection-limit", 5);
user_pref("network.http.sendRefererHeader", 0);
user_pref("network.prefetch-next", false);
user_pref("network.prefetching_next", true);
user_pref("network.proxy.socks_remote_dns", true);
user_pref("network.proxy.type", 0);
user_pref("nglayout.debug.disable_xul_cache", false);
user_pref("nglayout.initialpaint.delay", "0");
user_pref("pdfjs.firstRun", false);
user_pref("pdfjs.previousHandler.alwaysAskBeforeHandling", true);
user_pref("places.database.lastMaintenance", 1338831075);
user_pref("places.history.expiration.transient_current_max_pages", 87219);
user_pref("plugin.expose_full_path", true);
user_pref("pref.downloads.disable_button.edit_actions", false);
user_pref("pref.privacy.disable_button.cookie_exceptions", false);
user_pref("pref.privacy.disable_button.view_passwords", false);
user_pref("privacy.cpd.offlineApps", true);
user_pref("privacy.cpd.siteSettings", true);
user_pref("privacy.donottrackheader.enabled", true);
user_pref("privacy.sanitize.migrateFx3Prefs", true);
user_pref("privacy.sanitize.timeSpan", 0);
user_pref("security.dialog_enable_delay", 0);
user_pref("security.warn_viewing_mixed", false);
user_pref("services.sync.clients.lastSync", "0");
user_pref("services.sync.clients.lastSyncLocal", "0");
user_pref("services.sync.globalScore", 0);
user_pref("services.sync.migrated", true);
user_pref("services.sync.nextSync", 0);
user_pref("services.sync.prefs.sync.browser.download.manager.scanWhenDone", false);
user_pref("services.sync.prefs.sync.browser.safebrowsing.enabled", false);
user_pref("services.sync.prefs.sync.browser.safebrowsing.malware.enabled", false);
user_pref("services.sync.prefs.sync.browser.search.update", false);
user_pref("services.sync.prefs.sync.extensions.update.enabled", false);
user_pref("services.sync.prefs.sync.network.cookie.cookieBehavior", false);
user_pref("services.sync.tabs.lastSync", "0");
user_pref("services.sync.tabs.lastSyncLocal", "0");
user_pref("signon.autofillForms", false);
user_pref("spellchecker.dictionary", "ru");
user_pref("storage.vacuum.last.index", 0);
user_pref("storage.vacuum.last.places.sqlite", 1339419341);
user_pref("toolkit.startup.last_success", 1339502683);
user_pref("toolkit.telemetry.prompted", 2);
user_pref("toolkit.telemetry.rejected", true);
user_pref("ui.submenuDelay", 0);
user_pref("xpinstall.whitelist.add", "");
user_pref("xpinstall.whitelist.add.36", "");