Today I'm a bit sick.

Weirdly this does not trigger during testing.
PHP scope magic?

In this way it is possible to test the expression value.

See comment.

There are some weird quirks in DokuWiki.
1. The regex syntax for the Entry/Exit pattern is somewhat reduced.
2. Using a substitution type does not work.

Replaced with functions which wrap over static variable.

Directory name must match the plugin.

PHP default image prevents the installation via apt.