By default, closed and opened folders on the sidebar are shown with icon ⏵ and ⏷, but visually they are quite similar if you just take a quick glance at your sidebar. For me, telling which folders are currently open can take my brain 1s. I personally believe it can be reduced to 0.1s if it’s changed to ⊞ and ⊟. Is there a package that does that?
If there isn’t, can I easily do that myself? I have no experience developing packages.
Thanks!