Issue #2389455 by hussainweb, AjitS, Mile23, subhojit777, tibbsa, Ayesh: Clean-up system module test members - ensure property definition and use of camelCase naming convention

Issue #2453059 by Wim Leers: Set default render cache contexts: 'theme' + 'languages:' . LanguageInterface::TYPE_INTERFACE

Issue #2445743 by dawehner, Wim Leers: Allow views base tables and entity types to define additional cache contexts

Revert "Issue #2445743 by dawehner, Wim Leers: Allow views base tables and entity types to define additional cache contexts"

This reverts commit a87aff86.

Issue #2445743 by dawehner, Wim Leers: Allow views base tables and entity types to define additional cache contexts

Issue #2350837 by dawehner, Berdir, larowlan, Wim Leers: Convert most usages of EntityInterface::getSystemPath() to use routes

Issue #2040135 by Wim Leers, Berdir: Caches dependent on simple config are only invalidated on form submissions

Issue #2377117 by mglaman, rpayanm, pcambra: Replace all instances of entity_load('field_storage_config') and entity_load_multiple('field_storage_config') with static method calls

Issue #2350823 by lauriii, jhedstrom, Tim Bozeman, cilefen, davidhernandez, inqui, Cottser, xjm: Use the Classy theme in the Testing profile

Issue #2377115 by mglaman: Replace all instances of entity_load('field_config') and entity_load_multiple('field_config') with static method calls

Issue #2322233 by Temoor, Mirroar, estoyausente: Replace all instances of user_role_load(), entity_load('user_role') and entity_load_multiple('user_role') with static method calls.

Issue #2304987 by Berdir, Wim Leers: Fixed Don't invalidate cache tags of referenced entities, use entity list cache tags correctly, add test coverage for entity list cache tags.

Issue #2100343 by Berdir, fago, martin107, visabhishek, sriharsha.uppuluri, Yorirou: Remove 'fieldable' key in entity definitions in favour of 'field_ui_base_route'.

Issue #2340123 by Wim Leers: Setting cache tags can be tricky: use strings instead of nested arrays to improve DX.

Issue #2312093 by alexpott, yched, andypost, swentel | xjm: Rename FieldInstanceConfig to FieldConfig.

Issue #1976158 by Berdir | msonnabaum: Rename entity storage/list/form/render "controllers" to handlers.

Issue #2287727 by yched, swentel, alexpott: Rename Field[instance]Config classes and entity types (again).

Issue #2241229 by Wim Leers: Aggregator Feed & Item content entity types, and AggregatorFeedBlock should use cache tags.

Issue #2124957 by Wim Leers, catch: Replace 'content' cache tag with 'rendered' and use it sparingly.

Issue #2143291 by plach, alexpott, xjm, effulgentsia, pwolanin, swentel | yched: Clarify handling of field translatability.

Issue #2080343 by connork, izus, rahul.shinde, lokapujya | mrsinguyen: Remove Unused local variables from system module.

Issue #2099131 by jessebeach, Wim Leers, catch, Berdir, benjifisher, martin107, andypost: Use #pre_render pattern for entity render caching.

Issue #2217749 by Wim Leers, Jalandhar, visabhishek, damiankloip: Entity base class should provide standardized cache tags and built-in invalidation.

Issue #2185617 by Wim Leers, voidberg, drifter: Each page cache entry should have a theme cache tag.

Issue #2188565 by Wim Leers, Berdir: Test coverage for Comment, Custom Block, Node, Taxonomy Term and User entity cache tags.