In gem ckeditor v5.1.2: app/assets/config/manifest.js overrides main manifest.js application configuration - all directives of main application are losed after mount ckeditor gem (Rails 7.1.3.4).
According to the unspoken rules, the manifest file for a gem should be called: _manifest.js, i.e. in your case ckeditor_manifest.js (I don’t remember exactly where, but this topic was discussed earlier, and it was never reflected in the official Rails documentation).
In gem ckeditor v5.1.2: app/assets/config/manifest.js overrides main manifest.js application configuration - all directives of main application are losed after mount ckeditor gem (Rails 7.1.3.4). According to the unspoken rules, the manifest file for a gem should be called:_manifest.js, i.e. in your case ckeditor_manifest.js (I don’t remember exactly where, but this topic was discussed earlier, and it was never reflected in the official Rails documentation).