Hi,

I want to have a user role who can administrate content of Custom Blocks but not : Block Layout or Block Types.
So my client can change custom blocks content but not block layout or block types (I don't want at all he broke anything or even see how it is set).

I take a look at the core modules "block" and "block_content".
"block" module add a permission named "administer blocks" which is used in BlockContent entity to provide admin to it.

In fact, I want something like addding a new permission "administer blocks content" which only permits to manage BlockContent entity.

I have no idea how it is possible. I don't know yet how it is possible to override any kind of modules in Drupal 8 without use of hooks. It would be a dream it is possible to make and use custom class (or config file) which extends any module ones ;) Maybe there is a doc about it (??) or maybe it is very limited or impossible.

Thanks for your help.
I'm new to Drupal 8 (I start with 6 big web projects just the day D8 was released, I'm SF 1.x expert).

Sylvain