https://docs.lnav.org/en/latest/commands.html#adjust-log-tim...
That can be useful for doing minor alignments if clocks are slightly out of sync or doing timezone adjustments.
You can also adjust the time programmatically by updating the "time_offset" column in the "lnav_file" table:
https://docs.lnav.org/en/latest/sqltab.html#lnav-file
Sorry I don't have any examples written up to illustrate this at the moment...
With my old log merging program, you had to supply a regex with groups for the different timezone components and optionally a UTC offset. That worked really well but was a pain to set up. Typically I was using it to look at the same format of files all the time though, so in practice it wasn't that bad.
I'm not really a C/C++ person but maybe I'll try and hack on lnav a bit and see if I can figure out how to add timezone support.