The Licences of all text and images is the Creative Commons licence Attribution-ShareAlike (also used by Wikipedia at the date of writing this text) if not indicated otherwise.
The “if not indicated otherwise” does not mean it gets more restricted, just the opposite. Some things are not worth the hassle and some things do not even reach the necessary “Threshold of originality” to get the protection of copyright (e.g.: any mathematical formulas).
Computer-code snippets will get a licence more apt to computer-code, probably one of the free licences or even less.