The PHP manual does not include self in its list of keywords. A comment on the manual page suggests that self should be included, but it has been significantly downvoted. Does that mean that self is not a keyword?
The reason this matters is that the PSR-12 specification on coding style states that all PHP reserved keywords and types must be in lower case. The specification contains two links to lists of reserved keywords and types, but self does not appear in either of them. Does that mean that PSR-12 is silent on whether self should be lower case?