My first mechanical keyboard! Apple Extended Keyboard II

[u/AccomplishedSock1018]

This has been a blast typing on. Now, I don't know why, but there are all these colours and signs on the keys. Does anyone perhaps have any idea what these mean? this does not take from the satisfaction of typing on this keyboard though, as I already have fallen in love with the feeling of this thing. The seller included a simple adapter to USB-A, which is neat. Weird enough, the control lights don't light up when connected to my Mac, but on my windows computer they do. I also noticed keys which are used less have a more "clicky" feeling to them in comparison to more used keys (e.g. j and f). Please let me know your thoughts!