The following message is not displayed on the Template:Temporary Accounts/Header/sandbox page:
This is the template sandbox page for Template:Temporary Accounts/Header (diff). See also the companion subpage for test cases.
The following message is not displayed on the Template:Temporary Accounts/Header/sandbox page:
This is the template sandbox page for Template:Temporary Accounts/Header (diff). See also the companion subpage for test cases.
Because Module:Documentation isn't even called there at all. There's nothing it can do.