While I can find the frame rate of movie via -
$ mediainfo $somemovie.$format | grep Frame rate
Is there anything which tells the frame-rate of a sub file, (.srt) ?
srt-files are based on running-time, so the frame-rate doesn't matter. If a text is supposed to be shown at 0h10m10s to 0h10m15s, then it will be shown then - it doesn't matter if there are 10, 25, 50 or 100 frames video for each second.
However, sometimes the video-files may be slightly edited, so a subtitle-file made to another "version" of the video (eg. a movie), may not line-up perfectly or may drift. But this is not due to frame-rate.
From a srt-file - note the times, eg. from 0h03m22,520s to 0h03m23,873s:
(...) 18 00:03:22,520 --> 00:03:23,873 Manu... 19 00:03:24,040 --> 00:03:26,918 Manu, come please. Where is Radouan? 20 00:03:27,680 --> 00:03:29,989 Where is Radouan? -Come here. (...)