MegaPaint BLD

MegaPaint BLD is a really obscure graphic file format (probably raster) for the MegaPaint program, which, according to a page that's trying to get people to download a trial version of a program to convert it to PDF, was for "early types of personal computers, including Commodore 64, Atari and Amiga." No more specific information seems to be easily findable, though there are pages for this extension on lots of the exploitative sites that have auto-generated, not-very-informative pages on every file extension they can find on any list. This format does show up on the list of formats supported by some multi-format utilities (including XNView), which is likely how the other sites found out about it.