Best Practice on Changing a Theme

What is the best practice for changing theme template files?

In WordPress they have the child themes workflow to override pages in the original theme and not loose changes when the theme is updated. Does Grav have a similar work flow?

WordPress Child Themes

/themes/TwentyTen <-- original theme
/themes/TwentyTen-child <-- empty folder containing only files to override

I know about overriding the theme in yaml on the actual content page .md file (template:). Is it possible to just drop a template file (like default.html.twig) in a /user folder without copy/pasting the theme and updating the original theme template pages?

I did read the manual and remember something like that but now I cannot find it.

found it again in the Grav manuan, here is a link to Theme Inheritance