Manual:$wgEditSubmitButtonLabelPublish

Output: $wgEditSubmitButtonLabelPublish
Vary the 'save' labels to 'publish' for public wikis.
Introduced in version:1.28.0 (Gerrit change 296719; git #ba4532aa)
Removed in version:still in use
Allowed values:(boolean)
Default value:false

When $wgEditSubmitButtonLabelPublish is true, MediaWiki will label the button to store-to-database-and-show-to-others as "Publish page"/"Publish changes". If false, the default, they will be "Save page"/"Save changes".