FWIW, I wouldn't say it's obvious why the switch to the Table-Based Format explains why there's no need for the Appendices any more. The more relevant change is that these "Table Lists" (which are also named "DataProductList" files after you download them) came along a few years ago and now provide most of the info that the Appendices used to, aside from a sequence number, start & end positions, and the topics. The switch to the Table-Based Format means that the sequence number and start & end positions are no longer needed, but the geographic restrictions and the list of available summary levels and geographic components are still very important for summary file users. For that reason, it's problematic that there's nothing on the Table-Based Format pages that points users to the Table Lists.
When we started adding the 2022 files into IPUMS NHGIS last fall, I still had not yet encountered the Table Lists. We'd always used the Appendices instead. I recall looking for information like what the Appendices provide for quite a while before I encountered the Table Lists. It'd be great if someone at the Bureau could add a link to the Table Lists pages in a suitable place on the Table-Based Format pages.
Also, we never made use of the Topics list in the Appendices in our work, but if those would be easy to add to the Table Lists, I'd suggest re-adding them in case there are more users who are still looking for something like that.