The CMS Change Release Inventory for Internet-Only Manuals

 I've usually scanned for CMS transmittals of interest by googling "CMS transmittal 2021" and scrolling through the resulting webpages.

https://www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/2021-Transmittals

Another approach is a PDF regularly updated by CMS that keeps a running tally of current and recent transmittals which alter the "internet only manuals" or instructions to contractors.  Find it here:

https://www.cms.gov/Regulations-and-Guidance/Guidance/Manuals/Downloads/Futurepdf.pdf

Note that the file number in the PDF page below is actually a hotlink.

For an online inventory of updates to NCD edits, see here:

https://www.cms.gov/Medicare/Coverage/CoverageGenInfo/ICD10