2.61 Pragma Extensions_Allowed

Syntax:

pragma Extensions_Allowed (On | Off | All);

This configuration pragma enables (via the “On” or “All” argument) or disables (via the “Off” argument) the implementation extension mode; the pragma takes precedence over the -gnatX and -gnatX0 command switches.

If an argument of "On" is specified, the latest version of the Ada language is implemented (currently Ada 2022) and, in addition, a curated set of GNAT specific extensions are recognized. (See the list here here)

An argument of "All" has the same effect except that some extra experimental extensions are enabled (See the list here here)