This video shows how to customize the file name in OBS for normal recordings as well as replay/clips.
The default filename is:
%CCYY-%MM-%DD %hh-%mm-%ss
To change this format do the following steps:
Go to Settings
Select Advanced
Under Recording, go to Filename Formatting
To update Replay Buffer, follow the same steps but this time add a Prefix or Suffix for your replays/clips.
quik.video
quik.video/subscribe