Is it allowed to copy code from existing WordPress plugins to build own plugins?

Server Administration ForumIs it allowed to copy code from existing WordPress plugins to build own plugins?
willisupportz asked 10 months ago PPU : 5

I would like to copy code from existing WordPress plugins to create my own plugins. Is this allowed? In general it should be allowed to copy Open Source software. But I wonder how the plugins of WordPress are licensed becasue some of them come as paid pro plugins integrated into an Open Source WordPress system. Can anybody help me here?