Issue #3375850 by omkar.podey, hooroomoo, smustgrave, narendraR, tedbow: Broken Breadcrumb on Appearance tab

Issue #2577407 by vulcanr, jhodgdon, Sagar Ramgade, snehi, brahmjeet789, Manjit.Singh, Tony-Mac, ressa, xjm, cilefen, sajosh, ifrik, Charles Belov, Bojhan, David_Rothstein, Gábor Hojtsy, tkoleary, longwave, NickDickinsonWilde, nishantkumar155, shell_cm, greta_drupal, YesCT: Action of uploading module/theme files should consistently be called "Add", not "Install"

Issue #2646328 by alexpott, Wim Leers, David_Rothstein, aaronott, Ayesh: CSRF in update module manual check links

Issue #2010246 by tim.plunkett, tkuldeep17, plopesc, InternetDevels, pfrenssen, googletorp: Convert update_manager_install_form, update_manager_update_form, update_manager_update_ready_form to the new form interface.

Issue #2089635 by tim.plunkett, disasm, larowlan: Convert non-test non-form page callbacks to routes and controllers.

Issue #2051097 by dawehner, Manuel Garcia, tlattimore, neclimdul: Change 'pattern' to 'path' in *.routing.yml files.

Issue #1981368 by tim.plunkett, Crell, webchick: Convert all routes to 'module_name().foo_bar()' naming convention.

Issue #1938822 by sandhya.m, EllaTheHarpy, tim.plunkett, alexpott, YesCT: Convert update_status() to a new-style Controller.

Revert "Issue #1938822 by sandhya.m, EllaTheHarpy: Convert update_status() to a new-style Controller."

This reverts commit c7d74b3c.