The deployment of T239676 will introduce an option for all contributors to opt into the mobile wikitext editor, even in instances when the mobile visualeditor would have otherwise loaded by default. 
To ensure these contributors are appropriately accounted for in our analysis, we will need to add new tracking events that enable us to see which users opted into the mobile wikitext editor by way of the new "fallback workflow" T239676 will introduce.
Instrumentation to be added to VisualEditorFeatureUse. Proposed event names are below:
Event: A contributor is shown the fallback prompt
VEFU feature: mobileVisualFallback
VEFU action: context-show
Event: A contributor elects to use the fallback editor
VEFU action: fallback-confirm
What we would like to know
We would like to know...
- When/whether a contributor is shown the fallback prompt
- Whether they elect to use the fallback editor
- The instrumentation required to satisfy the "What we would like to know" requirements have been defined
- The instrumentation required to satisfy the "What we would like to know" requirements have been implemented
- E.g. a contributor in the A/B test could be assigned to the default-visual bucket, but elect to use the mobile wikitext editor if they felt the mobile visual editor was taking too long to load.