When you upload a song, you indicate whether it has copyright and who owns it, Then, whenever its played they pay the copyright owner based on an audience size basis, similar to Spotify.

If you don’t, the copyright owner informs Google, and they close that link.

Even if you have music playing in the background of an instructional video, the copyright holders will go after you.

Its about 40 cm high btw. Its huge.

They had lithium ion batteries in 1985. You could get lithium ion backed DRAM for the ZX-81, “keeps data for 10 years”. Nothing like enough power to move a bicycle or anything.