Can anyone provide some kind of a syllabus to help me figure out what there is to learn about it, starting from almost no knowledge at all?
I feel like it's a critical enough piece of modern web infrastructure that it's worth me taking the time to fully understand how to use it and what it's capable of.
This makes any attempt to debug and solve problems with it a total nightmare, like crawling through a tar pit. You might make it, but you're gonna feel all sticky and dirty coming out the other side.
That said, kudos to the developers, I use it every day, but I wish it were a lot simpler.
Getting this information out of the documentation is like squeezing water from a rock. It seems to be written of the opinion that you don't need to know how and what is going on, and if you do you probably already know.
I don't think most people really "learn" Webpack. Mostly they just tweak cut+paste examples and get back to value add work. You can definitely achieve 99% of whatever task you have without going down the warren of Webpack rabbit holes. You're committing no crime if you just relegate Webpack to the "get it working and forget it" bin; it does what it says on the tin and you can rely on it despite not being an expert.
EDIT: ok, some more context. You should be glad you haven’t had to deal with this shit show yet. Don’t walk willingly into it, there are much less painful tools like Rollup, Vite and Parcel around.