A few users have expressed confusion or concern about our implementation ordering strategy, as expressed in T363908. The ordering is based primarily on number of failing tests and speed of execution of the implementations, and the first -ranked implementation generally gets chosen when a function is called. It would be helpful to provide documentation and make it readily available.
[x] Provide a new documentation page (on mediawiki.org) explaining when and how reordering happens
[] In the metadata dialog, where we show the selected implementation, add a link to the doc page, with text perhaps something like "How chosen?"
[] If feasible, consider also adding a link to the doc page in the edit-message that we generate, in a function's page history, when that function's implementations get reordered