Which water pipe is it about?

Dear forum! Can someone tell me what type of pipe my water pipes are (see photo), if it can be recognized from the photo? That would help me a lot. It is an Elkhaus, which was built in 1993. Thank you very much in advance

Looks like plastic composite pipe to me. Take a utility knife and carefully scrape a small piece at a 90-degree angle over the line. If plastic peels off, it is most likely a PE composite pipe.

Now that it is light again, I have removed some of the foam and taken a new photo – now it is more visible. Could it be that this is a type of PPR pipe? That is, can I work on this pipe with a socket welding machine? Thank you and kind regards