I've never cared about that file but last week a weird problem appeared - something (unclear what) kept changing the permissions of bash history and every time I used the terminal, it would create ~/.bash_history-[number].tmp. These tmp files weren't temporary as their extension suggests. Normally a tmp file should disappear when you close the program that created it but these files didn't disappear and I had to delete them manually. So I put it to a test - changed the permissions back to normal, drove 2500 miles on ETS2 for a few hours and when I closed the game, bash history's permissions were changed again. The game has nothing to do with bash, so I seriously doubt that the game did the change. So I did the only remaining thing I could think of - changed the permissions back to normal and then made the file immutable. After I made it immutable, the terminal no longer saves history of commands (not that I care, anyway) but also the tmp files stopped appearing.
Once again my linux learning resource was... linux.