What exactly is action_name? (Maybe) Change its documentation.

[EPNW-Eric]

For context: We are currently discussing implementing a tracker solution based on the Tracking HTTP API.

The documentation lists action_name as one of the Recommended parameters. It also states that "you should provide as much information as you can" with regard to the parameters. We understand this as setting the recommended parameters as frequent as possible.

Here is the quoted description of action_name from the documentation:

action_name (recommended) — The title of the action being tracked. For page tracks this is used as page title. If enabled in your installation you may use the category tree structure in this field. For example, “game / register new user” would then create a group “game” and add the item “register new user” in it.

The second sentence of the quote makes it clear to me how to use action_name when tracking page views.

Now, I had a rather long discussion with one of my collegs on how to use action_name when not tracking a page view.
As a Recommended parameter, the documentation kind of suggests to set it in every tracking call if possible, but only gives advice on what to set it to when tracking page views.

Now, I view action_name more like a page_name and I only want to set it when tracking page views, while he wants to set it for every tracking call (to the name of the page the action happens on).

To prove my point, I did two things:

• I reffered to the JavaScript tracking API, which only uses action_name in logPageView. (Side question: Am I correct to treat the JavaScript implementation as a "Tracker Refference Implementation"?)
• I tracked an event using the event paramters e_c and e_a, and also set an action_name; The event was logged and I inspected the Matomo database directly, but found out that action_name for the event was recorded nowhere.

He on the other hand argued that:

• The documentation recommends it, so we should set it.
• Setting a parameter that might not be used doesn't hurt.

Since we could not come to an agreement on this matter, we are now asking what exactly action_name is and how/when we should use it?