The activation is a one-time process which is necessary so #Gazer can communicate with the PHP interpreter. If there is no activation, macOS will block any communication. For activation, the corresponding PHP interpreter must be selected in the Finder application. By right-clicking and selecting the entry Open in the context menu that appears, a query is generated. This query asks whether access to the PHP interpreter should be allowed. After confirming this, the PHP interpreter can be used in #Gazer.
There are basically no restrictions when choosing the PHP interpreter, but it should be accessible via the terminal application (command line). A good ready-to use solution is available from the MAMP development package that can be downloaded free of charge from the website https://www.mamp.info. This package already installs the required PHP interpreter in the Application folder, which already fulfills the first condition. The PHP interpreters can be found under the following path, where the x stands for the version number
/Applications/MAMP/bin/php/phpx.x.x/bin/php
Currently, (09/2021) it is recommended to use a PHP version of the 7.4.x series.