wiimpersonator is a tool that connects to Nintendo's update servers, and fetches information about any new system updates. Wiimpersonator can also fetch Wii U updates due to the Wii U having the same update system.
As of 3 April 2021, wiimpersonator no longer is checking for updates due to a dependency on the now-deprecated Python 2. Past reports are still available.
Note that the first 3 entries were not created on April 15; they were instead generated before Wiimpersonator went public. The first was from March 9th, the second from March 20th, and the third from March 22nd.