Currently the visualization tool does not say when "no data" is availability. When no data is avaliable it should say so.
Description
Description
Event Timeline
Comment Actions
This should be already possible via the Graph extension, see for example the first item on https://www.mediawiki.org/wiki/Extension:Graph/Interactive_Graph_Tutorial
Closing this task as on-wiki content like templates are local features and managed independently on each wiki, except for when a dedicated project tag on Phabricator exists.