WordPress comes with some standard colours for the block editor and some themes or plugins add their own or simply override them. This can happened during various times and places within WordPress.
If you tick “Add to block editor” my plugin will by default override those colours. Sometimes this does not work and therefore I added an option “Enforce colours” which forces WordPress to override or append.
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Oh, and by the way, I haven’t forgotten your suggestion from a few days ago.
I simply haven’t found the time to look into it yet.