My first bitcoin reimplementation was written in node.js and called bcoin[1]. So this is my second time reimplementing the bitcoin protocol, albeit in a very different language.

Bcoin was frequently used as a reference along with bitcoin core v0.8.0-v0.11.0 when I felt like double checking consensus functions (among other things).

As an aside, I personally think bitcoin core v0.8.0 is the best version of core if you want to learn bitcoin from it. It's a lot more straightforward than later versions. I personally don't enjoy reading any version beyond v0.11.0.

This is also the reason mako doesn't support taproot yet. That code is very new and isn't present in upstream bcoin. I could try to implement it from the BIPs alone, but I won't know what intricacies are present in the actual bitcoin core code until I actually read it.

[1] https://github.com/bcoin-org/bcoin

When you say "reading bitcoin core v0.8.0", do you mean reading the source code? I want to learn more about the fundamentals (technical part) of bitcoin, but am not sure if diving into the 600k+ lines of src code is worth it. Do you know any way to understand bitcoin (or cryptocurrencies in general)?

I highly recommend the books "Mastering Bitcoin" by Andreas Antonopoulos (technical, for beginners) and "Programming Bitcoin" by Jimmy Song (very technical, advanced).