Issue #3130107 by stefanos.petrakis, rpayanm, smustgrave, jungle: Extend unit test coverage for LanguageNegotiationContentEntity

Issue #3311563 by stefanos.petrakis, rpayanm, smustgrave, longwave, Wim Leers: Safeguarding against UnblockUser::execute()'s method unblocking the anonymous user

Issue #3239472 by stefanos.petrakis, danflanagan8, sjerdo, kporras07, alorenc, borutpiletic, tanc, benjifisher, alexpott, Kristen Pol, larowlan, longwave: preg_split in _filter_url breaks for long html tags

Issue #3130751 by stefanos.petrakis, Medha Kumari, larowlan, alexpott, jungle: Fix LanguageNegotiationContentEntity::getLangcode() errors thrown

Issue #3126127 by stefanos.petrakis, andypost, xjm, pooja saraah, Kristen Pol: Fix LanguageNegotiationMethodInterface::getLangcode() result docblock

Issue #3008028 by quietone, bserem, naresh_bavaskar, ravi.shankar, daffie, Gábor Hojtsy, phenaproxima, catch, Zekvyrin, stefanos.petrakis: Migrate D7 i18n menu links

Issue #3130438 by stefanos.petrakis, andypost, longwave: Inject page_cache_kill_switch service to LanguageNegotiationBrowser

Issue #3094536 by stefanos.petrakis, mcdruid, alexpott: PHP 7.1 Warning: A non-numeric value encountered in template_preprocess_pager()

Issue #2201789 by joelpittet, jjcarrion, stefanos.petrakis, wiifm, Geizt, lussoluca | Cottser: Don't print '_theme()' in twig_debug output.