Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system.

[philipp-classen]

Ghostery 10.3.9 error details:

Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system.

Originally reported here: #1653 (comment)

I have also seen it once after an extension update, but did not notice any problems. Afterwards, I could not reproduce.

[smalluban]

It is the browser artifact, generated in the first moment of loading extension (looks like parsed and optimized DNR rulesets):

I think it would be possible to re-produce the error, if the user uses an unpacked extension from the file system, and tries to load again the extension with that directory already created. However, I couldn't reproduce it.