I stumbled into an interesting unintended consequence relating to the interplay of Edge Chromium and EdgeHTML -- failure to display Favicons for Favorites imported from Edge Chromium into EdgeHTML.
As I reported earlier, in the immediate aftermath of the "Edge Deletes Edge" boondoggle, EdgeHTML failed to sync across the three Windows 10 devices I was using to test Edge Chromium (the two Windows 10 computers on which I had not installed Edge Chromium and the two Android devices on which I use Edge Android continued to sync as expected). I worked with Microsoft support for several days to resolve this issue, and eventually removed Edge Chromium from the three computers on which I was testing Edge Chromium, which did not work, and then doing a clean Windows 10 reinstall on two of the three, which resolved the sync-across-devices issue. I have not yet reinstalled Edge Chromium on any of the computers, and may wait until the Beta version is released before I do so, because I need to have two stable browsers working (in my case, Firefox and EdgeHTML at this point).
As part of the remove/reinstall process, because I had been using Edge Chromium rather than EdgeHTML as my primary browsing platform for several months, I saved Edge Chromium Favorites to an HTML file, and then imported those bookmarks into EdgeHTML as part of the Windows 10 reinstall process.
At that point, EdgeHTML failed to display Favicons in the Favorites toolbar or Favorites menu, showing just the star as the Favicon, something that normally occurs only when a website has not designated a Favicon. The only Favicons that were displayed were a link to Bing and a link to this forum, both Microsoft sites. Oddly, Outlook Mail, also a Microsoft site, did not display, and does not to this day, even after the workaround described below. As the devices on which I use EdgeHTML (both the three on which I reinstalled Windows 10 and the two which did not need a reinstall) synced, the Favicons disappeared from all five Windows 10 computers, but the devices using Edge Android where unaffected.
As I started looking into that issue, I discovered a host of posts/discussions dating back to the 2016 Windows 10 Anniversary update, all complaining that EdgeHTML failed to display Favicons when Google Chrome favorites were imported into EdgeHTML, both as part of the "Import Favorites from Chrome" process and as part of the "Import from File" process. It seems that something similar occurred in this specific case, which suggests that the root cause is related to the way in which Favicons are stored is in the Chromium base common to both Google Chrome and Edge Chromium.
If anyone else experiences problems with Favicons failing to display after importing from Google Chrome or Edge Chromium, the workaround is simple, but tedious. Open the affected website, change the Favorite setting for that website to "Show icon only", wait until the Favicon appears, and then switch back to "Show name and icon". In some cases, the Favicon will not appear until I sign into the website, but that is not universal.
An odd result, and minor, and one that I do not think will affect the EdgeHTML to Edge Chromium migration going forward, since the issue appears to be one way, affecting only importing Favorites from Chromium-based browsers into EdgeHTML, and the migration process from EdgeHTML to Edge Chromium works in the other direction.