You’re looking at what amounts to an unrecognized data file; a binary file. the data in the file might be a document, or an executable app, or who-knows-what.
Want macOS to tell you about the file format?
Launch Terminal app.
Type the following “file “ command, followed by a space or two, and do not press the return key:
file
Go back to the GUI, and drag one of the downloaded files into the Terminal app window.
That’ll drag the filename and its path into the command. Not the file itself, but the file specification.
You’ll get something that looks like the following command, but with different text mixed together with the slashes:
file /Users/mrhoffman/Downloads/MysteryFile.Whatever
Now press the return key.
Tell us what the file command reports about the file you just told it to examine.