arrays & variable extensions are going to break

[hcooper]

The Arrays & Variables extensions are going to break "sometime" in the future.

This extension is incompatible with plans to parallelize parsing, as is intended by the use of Parsoid. Therefore, the future of this extension is uncertain, and it is expected to become incompatible with the standard MediaWiki parser within a few years. For further information, see T250963 and No support for sequential, in-order processing of extension tags.

We use them aaalllllll over the place :-(

https://www.mediawiki.org/wiki/Extension:Arrays
https://www.mediawiki.org/wiki/Extension:Variables