Filesource in base installation needs a little tweak.
Add in at line 75 after global $content
// to stop empty filesources from producing an error
if ( !isset($content['file_binding']) ) $content['file_binding'] = '';
if(substr(trim($content[$vals]),0,$count) == $include.' MODX_BASE_PATH.\'assets/'.$elm_name.'/')
This prevents a plugin with no static file source from producing a warning.
You can see the warning if you edit CodeMirror.
There is an error when editing a plugin with no Configuration. This is displayed
TypeError: Cannot read properties of undefined (reading 'label')