Copied theme not displaying in admin interface

Hi there,

I have created a theme by copying one from an existing site. The theme displays fine in the published website, but I can’t get it to show on Admin > Installed themes.

It’s not a major problem, since the theme works, but I’m confused why it might not be showing in Admin.

FYI - I didn’t use bin/plugin devtools newtheme to create the theme. I just copied an existing theme that was working on another site. Is there anything I can do in the backend to replicate the actions of bin/plugin devtools newtheme ?