Extension:NumerAlpha lets you add auto-incrementing numbers, letters and roman numerals, with options to reset them at any point and to organise those numerals, etc. into groups. It is incredibly useful, for instance to make sure SMW's subobjects can be numbered and queried in the order in which they appear on the page. You can achieve some of that with the Variables extension, too, but its future happens to be at stake.

• https://www.mediawiki.org/wiki/Extension:NumerAlpha
• https://gerrit.wikimedia.org/r/mediawiki/extensions/NumerAlpha

Unfortunately, NumerAlpha is listed as an extension which in its current form, is incompatible with "Parsoid's future plans for parallellized parsing". That may be true already for MW 1.40.

The extension should be rewritten to become Parsoid-compatible. It is probably helpful to have a look at the way the Cite extension has dealt with a similar issue in its approach to autonumbering and grouping references.