The Licences of all text and images is the Creative Commons licence Attribution (CC-BY) if not indicated otherwise.
The “if not indicated otherwise” may not mean it gets more restricted, just the opposite in most cases. 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 less if possible.