7 files declare their use of ContextReactionPluginBase in Context 8.4

Blocks.php in src/Plugin/ContextReaction/Blocks.php

BodyClass.php in src/Plugin/ContextReaction/BodyClass.php

Menu.php in src/Plugin/ContextReaction/Menu.php

PageTemplateSuggestions.php in src/Plugin/ContextReaction/PageTemplateSuggestions.php

PageTitle.php in src/Plugin/ContextReaction/PageTitle.php

Regions.php in src/Plugin/ContextReaction/Regions.php

Theme.php in src/Plugin/ContextReaction/Theme.php