You can find these strings in the raw .txt versions of major corporate filings:
Sites like Disclosure Quest archive these raw text files, where the string is visible to anyone searching for specific file extensions within government data. Conclusion M4C.7z
It appears in thousands of documents, such as Form 424B2 or FWP filings. You can find these strings in the raw
The sequence "4C.7z" is simply a coincidental result of the encoding process. It is not a real 7-Zip file, nor is it a hidden "leaked" archive. Where You’ll Find It M4C.7z