The current state is,
https://github.com/wikimedia/operations-mediawiki-config/blob/master/wmf-config/InitialiseSettings.php#L28379-L28388
```
'wgParserEnableLegacyMediaDOM' => [
'default' => true,
'group0' => false,
'test2wiki' => false,
'wikitech' => false,
// Careful with these, since they can partake in cross-wiki inclusion.
// See T51097#7401266
'metawiki' => true,
'commonswiki' => true,
],
```
Roughs steps would be,
[x] group0
[] opt-in wikis
[x] enwikivoyage - https://en.wikivoyage.org/wiki/Wikivoyage:Travellers%27_pub#Images
[x] cswiki - https://cs.wikipedia.org/wiki/Wikipedie:Pod_l%C3%ADpou_(technika)#Zm%C4%9Bna_v_HTML_k%C3%B3du_obr%C3%A1zk%C5%AF
[x] viwiki - https://vi.wikipedia.org/wiki/Wikipedia:Th%E1%BA%A3o_lu%E1%BA%ADn#Thay_%C4%91%E1%BB%95i_%C4%91%E1%BB%91i_v%E1%BB%9Bi_code_h%C3%ACnh_%E1%BA%A3nh_HTML
[x] itwiki - https://it.wikipedia.org/wiki/Wikipedia:Bar/Discussioni/Aggiornamento_del_parser_per_le_immagini:_vogliamo_testarlo%3F
[] group1 -(metawiki, commonswiki)
[] group2 +(metawiki, commonswiki)
[] default
but we'd like to get some wikis to opt-in beforehand
---
More information about what this flag enables at https://www.mediawiki.org/wiki/Parsoid/Parser_Unification/Media_structure/FAQ