Not sure if this is a useful picture but I have some copper pipe that is green with corrosion / oxidation and wondering if this is something I should replace. And what the cause would be? Is it galvanic or something else?
Here’s another photo with example of nearby solder joints.
For the solder joints, get a nice hot (but not scalding) bucket of water (perhaps with a spoonful of baking soda in it) and a rag and wipe them down if they are particularly green - that is generally failure to remove/clean flux after soldering.
Nothing there looks particularly dire - the above is basically preventative maintenance to reduce any further corrosion from leftover flux before it becomes an issue. It's finally doing what the person who soldered these should have done, probably decades ago (nice char on the framing, too!)
Not galvanic, most likely cosmetic/surface. Apparently it is occasionally wet with condensation. If it is wetted from a leak somewhere else, you have a different problem. I would clean it with sandpaper and watch it to determine how it is getting wet.
