Firefox on MacOS: Default filename when downloading
My solution was to make an Automator workflow to run a shell script, and map it to a universal keyboard shortcut. This has been very useful to me, so here it is:

# echo `date +"%Y-%m-%d "` + " "
A=`date +%F`
echo "$A "




Open Automator and create new workflow.



Set workflow to receive text from any application, choose to replace the selected text and add Run Shell Script. Choose /bin/bash and pass input to stdin. Paste the script and save.


Go to System Preferences, choose Keyboard and Shortcuts. Choose Services, find yours on the list and map a shortcut.