Manual:$wgContentHandlerUseDB

Content Models and Handlers
MediaWiki allows for page content types other than wikitext. It offers built-in support for JavaScript, CSS, JSON and plain text. Extensions can use MediaWiki's ContentHandler mechanism to add new content models for accepting different formats and controlling how they are rendered, stored and edited.
About
About the ContentHandler Content handlers and their implementation
Usage
Changing the content model of a page Changing the content model of a namespace Extensions using the ContentHandler Adding content models with an extension Examples: includes (part of Examples ) Markdown
Configuration settings
$wgContentHandlers $wgNamespaceContentModels $wgContentHandlerTextFallback $wgContentHandlerUseDB
Support and development Latest technical documentation (Git) Phabricator

Miscellaneous settings: $wgContentHandlerUseDB
Whether to use the database fields introduced by the ContentHandler facility
Introduced in version:	1.21.0
Deprecated in version:	1.34.0 (Gerrit change 535666; git #165d3cc5)
Removed in version:	1.35.0 (Gerrit change 589018; git #385ab887)
Allowed values:	(boolean)
Default value:	true
Other settings: Alphabetical | By function

Details

Set to false to disable use of the database fields introduced by the ContentHandler facility. This way, the ContentHandler facility can be used without any additional information in the database. A page's content model is then derived solely from the page's title. This however means that changing a page's default model (e.g. using $wgNamespaceContentModels ) will break the page and/or make the content inaccessible. This also means that pages can not be moved to a title that would default to a different content model.

Overall, set to false, no database updates are needed, but content handling is less robust and less flexible.