When they use the term 'dumpster diving', does this just mean searching through disposals for gadgets or tech or something else?

A friend of mine dumpster dives and I've gone with her. Better during the cold months or the smells will knock you out. She has found all kinds of stuff. It's not always about a dumpster per say. Sometimes it's roadside or curbside. In my state anything left outside of a donation box is trash. You'd be amazed at what gets tossed.