Comment by CrendKing

I just tested. 7-Zip is already doing exactly what the author's recovery tool does: if I delete the metadata at the end of the file, it still can open and extract files, while complaining about the harmless "Unexepcet end of data". Further, even if I delete the actual content of the last file, it still can show the directory structure, it just can't extract data of the last file.