(Per a discussion yesterday with @Jdlrobson and @Groceryheist:)
The [[https://meta.wikimedia.org/wiki/Schema:ReadingDepth |ReadingDepth schema]] should not send events for user actions that are not considered [[https://meta.wikimedia.org/wiki/Research:Page_view|page views]] - in particular, [[https://meta.wikimedia.org/wiki/Research:Page_view#Are_edits_considered_pageviews? | edits]] and action pages like `action=history` URLs should be excluded.
Special pages (namespace -1) can be left as is. (There is some value in having data for them too, which outweighs consistency with the pageview definition in this case - the [[https://meta.wikimedia.org/wiki/Research:Page_view#Are_Special:_pages_considered_pageviews? |pageview definition FAQ]] about this is a bit ambiguous and not entirely correct anyway.)
= Developer notes
Currently ReadingDepth does not check the value of wgAction meaning ReadingDepth events are sent on https://en.wikipedia.org/wiki/Spain?action=edit, https://en.wikipedia.org/wiki/Spain?action=history etc..
A conditional should be added to prohibit this.