On a wiki not using a full remote repository configuration but using the InstantCommons quick settings, the multimediaviewer-repository message contains the local wiki name.
[ Bug analysis ]
This remote repository name is defined in the LIP.setRepoDisplayName method:
displayname = displayname || mw.config.get( 'wgSiteName' );
This method is called in resources/ext.multimediaViewer/ext.multimediaViewer.js:
ui.setRepoDisplayName( repoData.displayname, repoData.isLocal );
The bug has been introduced in change Ife8293c86683ea914b1a5a60000584b501d92e55 and the new data model, where repoData.displayname doesn't seem to be set when using $wgInstantCommons instead of a full foreign repository configuration.
Version: unspecified
Severity: normal