Customizer "Additional CSS" panel is missing on multisite for administrators

[jakeparis]

In a multisite instance, any non-superadmin user can not access the Additional CSS panel in the customizer.

I assume this is a bug, as why would a site administrator not be allowed to add additional css.

According to wp-includes/class-wp-customize-manager.php:5746 (WordPress 6.3), the edit_css capability should allow access to this panel, however adding that capability to the role did not allow access.

I've seen this error in both WordPress 6.2 and 6.3.

[dlh]

Hi @jakeparis, and welcome back to Trac!

The behavior that you describe is the expected behavior on multisite installations. The edit_css capability is meant to map to the behavior of the unfiltered_html capability, which is granted to only super administrators by default on multisite installations.

The place to look is ​the `map_meta_cap()` function. See also ticket:35395#comment:50, ticket:35395#comment:78, and elsewhere in #35395 for background on the decision.