Imagine I have few kilograms of resistors, capacitors, transistors etc and I want to make an amplifier of sound frequencies. How to see on GitHub all 1-channel amps of class A, having 5-15W of output power, using no more items than I have or can buy in my town, and no SMD, and having a PCB layout for saving my time, and not having a power supply on that layout?
This is an example of my typical real goal and I can achieve this kind of goals in old fashioned way: using paper journals like "Radio" (a famous Soviet journal on electronics) or websites like vrtp.ru radiokot.ru (not an advertisement, those are real sources of schematics which I use in my hobby electronics projects) but this approach has a serious problem - these designs has been curated by "benevolent dictators", and I can not edit those for public even if I am sure there is some better ways to achieve same results. Also those resources might have minor problems like missing images from other websites which may be crucial for building this or that schematics.
Also your question has a second answer - I am not that big fun of electronics and those resources more than fullfill my beginner asks of making electronic devices but I have a hobby research project on VCS for general purposes so I am interested to see more of different approaches.
Many semiconductor manufacturers publish application notes with partial to full designs. Linear Technology app notes were probably the best example of this.
I use github for embedded projects: code, schematics, PCB artwork, drawings, etc. Haven't found it limiting in any way.
What else are you looking for?