Does anyone know how I can merge/deduplicate contacts in a .vcf vcard file?
Tonto2 is a python 3/Qt graphical app that runs on desktops. It's main purpose is not to manipulate *.vcf files, but the appendix to the instruction pages tells how, anyway. Tonto2 uses a spread-sheet-like presentation paradigm. With appropriate magical mystical spells, you can import *.vcf as *.csv and sort the *.csv by last-name, phone-number, eMail, zip-code, or whatever. It won't de-dup, but you can spot the duplicates easier once they're collated next to one another in one sequence or another. Show just the significant attributes. Probably you'll want to sort, look, sort, and look again. Killing entries is nearly as simple as checking them off. FAIR WARNING: This process is time consuming, frustrating, and fraught with peril. Keep several versions of your address list until you're sure the final is the one you want to keep forever. My experience is that I always find stuff I want to keep in each of all (sometimes more than two) duplicate entries, so deleting the dup's is not what's called for. Merging means manually copying from one entry and pasting into another. Due to the judgemental nature of how to handle conflicting and out-of-date info, I've hesitated to try to automate the process.
Yes it is except when it isn't. Maybe there's a reason practically no Adwaita theme alternatives ship with Debian. Maybe not. But, using Gnome, it's the default theme or nothing. I have to admit I don't know from themes. However, there are lots of Gnome themes available from theme peddlers.
Recently I became fed to the teeth with claws-mail, which is a GTK app. In Adwaita the foreground font color is too dark (gray) on top of the background highlight (blue). My eyesight had deteriorated to the point that I just couldn't read the Subject of the current eMail, so I shopped for a new theme that would be ... adequate. I didn't have time to try them all.
I settled on Ant by EliverLara. In this theme foreground font color (white) on background highlight (salmon) is just barely visible. I use it only for claws-mail:
> env GTK_THEME=Ant claws-mail