Thumbs.db - filename illegal - huh?

[Julix91]

Tried downloading https://github.com/woocommerce/woocommerce/tree/release/3.0/templates with this and it didn't work.

In the extensions tab chrome said There were warnings when trying to install this extension: Cannot load extension with file or directory name Thumbs.db. The filename is illegal.

But the extension icon appears, popup works and the example downloaded just fine. What am I missing?