As with the similar request in Auto-connect and greedy plug behaviour for gtk-theme-yaru-mate and icon-theme-yaru-mate I have vetted both the snap and the publisher.
Looking at the current gtk-theme-pop snap it only appears to contain images (including Windows ico and cur files), css, GTK resource / gtkrc files etc and the snap yaml only declares the content slots as named above, there are no hooks/daemons/apps etc.
The publisher has been vetted so +1 from me for global auto-connect with greedy plugs for gtk-theme-pop.
In the interest of expedience, I have gone ahead and granted this with just my +1 vote - can other @reviewers please chime in if you feel this is inappropriate and please vote so if needed we can revert this ASAP.