Activity detail page was missing average speed. Climbing was also missing on phones. Both fixed.
Interval fields now include “Work > FTP” or “WAR” (work above redline) in Seiler terminology. For old activities you need to make a dummy edit to an interval to re-analyse and get this stat.
The average comes from Strava and is based on moving speed.
Afaik, the only way this would be influenced by (long) breaks, is if you have recorded the activity on a device, or in a way, that doesn’t distinguish this.
I.e. on most bike computers (and I think also in most mobile apps), you can set auto-pause on, which would record both. Strava will then only use your moving time to calculate averages.