I wanted to know what does the "lrt" parameter means in an image hit, and why it is present sometimes and sometimes it isn't although it is the same custom link? This query parameter is not listed in the documentation here.
the "lrt" query parameter
data collectionimageQuery ParameterQuery String Parameter
The 'lrt' parameter stands for "last request timing" and shows the roundtrip time for the last request, i.e. it is only sent if there is more than one request going out from a page (or if it is an SPA).