[Weary Tourist]

Create a Microsoft Word document called Fred.doc, and rename it to Fred.htm which is what webpages are normally called. Open that in a browser you would see gibberish with some bits in English.

Would that be similar to what you see ?

If so then it may be the case that either :-
a. You are saving a file as the wrong file type

or

b. the website is doing this for some reason to protect something they created, or perhaps to give you some malicious file that could become active when renamed.

Hope that makes sense.