XF 2.3 Merging Outdated Templates

[VisEntities]

Can someone tell me what each action button does? (There was an article talking about this but I can't find it anywhere)

 

[Kirby]

Resolve using parent version uses the parent vesion (code snippet above the buttons), Resolve using both uses both code snippets and Resolve using custom version uses the custom version (code snippet below the buttons).

 

[VisEntities]

Resolve using parent version uses the parent vesion (code snippet above the buttons), Resolve using both uses both code snippets and Resolve using custom version uses the custom version (code snippet below the buttons).

I still don't know which to choose... What does parent mean? Is it the default unmodified?