What I do to look at new versions of firefox:

When I'm trying to understand what has changed beteen firefox
releases or betas, I've been using diff -Nur -X exclusions with an
exclusions file which allowed me to drop (by name) certain files I
was not interested in.

Before that I used to use diff -Naur, but at some point in the
distant past I hit unreadable (hex) code in certain i10n or i18n
files (diff assumed ASCII, they were something else).  I *think*
that those files maybe no longer exist, haven't seen anythong odd
recently.

The problems with that diff -Nur -X exclusions approach were that
the diff took a very long time (4 or 5 minutes), it included
directories I have no interest in re BLFS (e.g. '/test/' and its
variations), and even between two beta versions there was a lot of
output.

Now that firefox-113.0betas are available I have noticed that the
minimum versions of dependencies were unchanged.  That made me wonder
if it would be possible to diff agaisnt the current stable release
and get a usable diff to look at.  Spoiler: although I've cut it
down, it's still too big to do anything other than skim it.

After a couple of days of intermittent hacking I've got a perl script
which mostly works to separate the diff into '.slim' and '.skipped'
files (a few .css and .json files sneak into the 'slim' output).

I've now altered it to also handle seamonkey and thunderbird.  On my
test machine (rather slow by modern standards) it takes towards a
minute to diff and split  recent versions.

The script is in this directory, called 'slimfox'.  I've given this
the MIT license because I (eventually) found most of the perl parts
online.  Works with perl-5.36.2.

Aside:  Getting my head around current perl takes a while, it was 4
years ago that I last used it.

Also here are my notes on finding the minimum versions required by
firefox.

share annd enjoy (or go stick your head in a pig) - google Sirius
Cybernetics if you don't grok that.

ĸen