Look for "v65536" or higher in the filename; this usually denotes the first major update version for Switch titles.
This is a compressed version of an NSP. It is much smaller in size, which is great for slow internet connections, but it requires a compatible installer (like Tinfoil or DBI) to decompress it during installation. How to Install the Clannad Update clannad switch rom nsp update link
When searching for a link, you will likely encounter two main file types: Look for "v65536" or higher in the filename;