Users can obtain a FGameplayTag reference by calling FGameplayTag::RequestGameplayTag(TagName) passing in a path like MyCategory.MyGameplayTag.
Users can rename INI-defined tags in the editor via the Gameplay Tag Manager in project settings by right clicking a tag and choosing Rename. This results in a +GameplayTagRedirects entry in DefaultGameplayTags.ini. Thanks to this redirect assets will properly use the new gameplay tag path.
Code that still calls FGameplayTag::RequestGameplayTag() with the old tag name will fail to resolve the renamed tag. FGameplayTag::RequestGameplayTag() should take into account tag redirects so that renaming a gameplay tag in the editor doesn't result in code being unable to resolve it.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-194640 in the post.