Limiting the amount of RAM your main user uses with
rctl(8) can lessen the amount of times that Firefox crashes, as it runs under that user. For instance, your user could be eternalnoob. Despite using that as a group is overly vague, your main user needs to be limited in RAM usage anyway for all purposes, and leave room for the kernel to operate. This has done wonders for my computer, as it doesn't crash every time, but it still crashes when I have too many tabs open and get on a runaway intensive site. Still, when my computer, Xorg or Firefox crashes, it doesn't freeze up, where it requires manually disconnecting the power to my computer like it used to.
Firefox doesn't have a group at this time, however, gecko can be added as a group and made to be default with a bug report.
https://docs.freebsd.org/en/books/porters-handbook/book/#users-and-groups. gecko as a group,
/usr/ports/Mk/bsd.gecko.mk, could cover both Firefox and Thunderbird. I'm not able to get on this, at least not any time soon. Hopefully some of the many people who few are experts who use Firefox and/or Thunderbird work on this.
Thread limiting-and-dedicating-memory-cpu-usage.89545 mentions some details of the above, including how to use
rctl.conf(5). Doing that causes a major improvement for Firefox performance as described above, although this process could use more information.
