Can't find documentation for this call

Hi all,
I have been working with the API quite well for some months but I found this GET call through a library on github:

qualtrics.com/API/v3/surveys/{surveyId}

Unfortunately, I can't find the documentation page for this call.
It gives a JSON object very similar to that from the survey definitions:

qualtrics.com/API/v3/survey-definitions/{surveyId}

However there are some key differences such as the absence of the exportColumnMap in the survey-definitions call.
Any information on these things would help me greatly:

1. Link to the documentation from the first call


2. Explanation of the intended differences


3. Information about the exportColumnMap portion of the first call. In particular, I'm curious why loop and merge questions don't give the literal column names you get when exporting responses. They're suffixed with the loop number in parentheses from the API call but the data export tags these with #loop_number

Thank you!