Title::isValidMoveTarget has been deprecated since 1.25 in favor of MovePage, but is still used in a couple of places. All usages should be replaced, and the method should be hard-deprecated (should call wfDeprecated()), and scheduled for removal in 1.34.
Related Gerrit Patches:
|mediawiki/core : master||Hard-deprecation of Title::isValidMoveTarget|
|Open||None||T208786 Untangle MediaHandler, FileRepo, File, Title and Linker|
|Open||Hknust||T214317 Phase out deprecated Title::isValidMoveTarget|