Released version 5.99.3 with support for icon themeing.
As of 5.99.3 the betas have support for proper icon themeing with support for using different icon themes for light and dark mode and calibre switches between them automatically. In order to use icons from themes that support your plugin you should pass the plugin name to the get_icons() function to load an icon. For example:
Code:
icon = get_icons('owp_sigil.png', 'Open With')
this will load the owp_sigil.png plugin from the users installed icon theme, if present, falling back to the image in the plugin zip file. Note that if you use kiwidude's code for loading icons, you will need to adjust it, as the way it loads themed icons will no longer work.