Launcher creates extremely large log files

Over the last few weeks, I've been discovering enormous launcher_log.txt files in my .minecraft directory. 15 GB, 9 GB, 6 GB, and most recently 8 GB. I'm having trouble finding a way to open them to see inside, but one program seems to show a huge swathe of unknown (newline?) characters, bookended by actual logs. I'll attach it, minus the gigabytes of what seem to be newline characters.

I've noticed this seems to happen when I've had Java edition open for a few days, using my localhost server without logging off/restarting. It seems to also be when the launcher receives an update, but I'm not certain of that. I've also noticed, in conjunction, that the launcher is occasionally extremely slow to open, often opening about 5 minutes after I click the icon and after I've given up and moved on. Usually the only way to fix this is a force quit. I'm not sure if this is related, but I think it's worth mentioning.

Edit: Using hexdump, the unknown characters seem to be null characters, 0x00. I'm unsure if this is from the original file or due to my attempts at opening it, but I would put my money on them being from the original file.