boot.pnd.stl

Certificate trust list

An .stl file on Windows contains a certificate trust list. The file is a signed list of certificate hashes, for example the trusted root certificates in authroot.stl and the blocked certificates in disallowedcert.stl. The CryptoAPI of Windows updates and reads these lists. In 3D printing, the same extension marks stereolithography models, a different format. The content thus depends on the source.

A file extension is only a part of the file name. It does not give a guarantee about the format or the content of a file. But on Windows, the extension selects the program that opens the file.