Can't get rid of markdown extension I didn't install

I've started redacting markdown files inside VSCode (currently VS Codium, but I face the same issue in VSCode as well). What bothers me is that I see an odd preview with Chinese hieroglyphs everywhere: I have no markdown extension installed (as seen on the left side of the screenshot). I tried to search for it, found extension's repo and looked for any similarly named files at %USERPROFILE%\.vscode-oss\extensions, but to no avail. Is there a way to find any markdown-related settings or somehow force the app to use a standard markdown editor or another extension? Thanks in advance.

Thanks to the great comment by rioV8 decided to just go through it manually.
Turns out, that the "Office Viewer" extension is causing it.
While I wanted to find a way to change it without deleting the extension, technically the question is answered.