There are several records in this data set that list the wrong type of technology, for what AT&T actually provides at that plan level.
3 records list as "Internet Basic 1.5", and using fiber
3 records list as "Internet Basic 5", and using fiber
Internet Basic is entirely IPBB (fiber to the neighborhood, but copper to the premises, as a way to work around the signal degradation DSL suffers over distances) or DSL based.
Similarly, there is 1 record listed as "AT&T FIBER INTERNET 300", which lists its technology as "Not Fiber".
Do you know whether these records were provided by AT&T with these values, or is this something that happened in preparing the data set for publication?
Sources:
Current page with AT&T's plan breakdown: https://about.att.com/sites/broadband/performance
Wayback Machine copy of that page from April 14, 2022 (relevant to the timestamps in the data set): https://web.archive.org/web/20220414012818/https://about.att.com/sites/broadband/performance