As a general best practice:
- an app published on AppSource should add custom fields on a dedicated new tab instead of adding fields in a standard tab
- if this is not possible, add fields as last of the tab (not after or before other fields)
- please always avoid to move standard fields from extensions
- removing or renaming a tab in a standard page is a breaking change. Normally it’s rare that this happens, but you should always test your apps with a new release to avoid breaking things. The only way to avoid this is point 1 on this list.