I'm looking at old X-men issues, most list Marvel Girl as one of the appearing members. Which makes sense because Jean Grey was Marvel Girl for quite a while. However if you click the link, it takes you to Marvel Girl, who is now Rachel Summers.
So technically if people are looking for references for Marvel Girl (Rachel) they might look in really old X-men issues when her first appearance is Uncanny X-men #141.
Should all mantle characters have reference to earlier wielders?
It seems that people come to Comic Vine as a reference to find which comic a character appears in could be hopelessly lost if looking for mantle characters like: