Don't think this series is in the MBU though, despite Yankee protag-kun having a mechanical buddy. Setting looks different, and it's not grouped together with the other MBU comics under the artist's Twitter "Moments" page.

NNescio said:

Don't think this series is in the MBU though, despite Yankee protag-kun having a mechanical buddy. Setting looks different, and it's not grouped together with the other MBU comics under the artist's Twitter "Moments" page.

This could have happened long before MBU the world war that messed up MBU's setting.

While it could, it's best to not include the tag for now unless proven otherwise.