I've punted this for years, but now just want to get it solved.
When editing and saving and existing file through the Admin Panel (like an .md file), the file permission changes from my server default of 664 to 644. I've got around it for years by running a quick bash script to re-adjust all the perms.
This problem becomes increasingly frustrating when trying to work with an IDE and the Admin Panel at the same time.
Its a local development server running Apache, with ownership as www-data:group-name, with my user and www-data assigned to group-name. Files are 664, folders 775.
I see you can set image cache perms in system.yaml. Is there any way to set default file perms?
Thanks.