Regarding the mask, in backend mask have default configurations such as below:
general.json => typo3conf/mask.json
frontend.content => fileadmin/templates/content/
frontend.layouts => fileadmin/templates/content/Layouts/
frontend.partials => fileadmin/templates/content/Partials/
backend.backend => fileadmin/templates/backend/
backend.layouts_backend => fileadmin/templates/backend/Layouts/
backend.partials_backend => fileadmin/templates/backend/Partials/
backend.preview => fileadmin/templates/preview/
While installing our theme extension, we need to change the above mask configuration option values like below:
general.json => typo3conf/ext/<extension_key>/mask.json
frontend.content => fileadmin/<extension_key>/templates/content/
frontend.layouts => fileadmin/<extension_key>/templates/content/Layouts/
frontend.partials => fileadmin/<extension_key>/templates/content/Partials/
backend.backend => fileadmin/<extension_key>/templates/backend/
backend.layouts_backend => fileadmin/<extension_key>/templates/backend/Layouts/
backend.partials_backend => fileadmin/<extension_key>/templates/backend/Partials/
backend.preview => fileadmin/<extension_key>/templates/preview/
We tried like below, but its not working:
plugin.tx_mask.general.json = EXT:user_ss4u/mask.json
module.tx_mask.general.json = EXT:user_ss4u/mask.json