I created a mediawiki page to list and illustrate all the rendering options.
The page contains two columns: one rendering a mapframe, and one rendering an example image with the same options.

Here it is:
https://www.mediawiki.org/wiki/Help:Extension:Kartographer/Rendering_options

-> @CKoerner_WMF, can you link it to Help:Extension:Kartographer please ? (I need your help dealing with the <translate> tags)

Having such side-to-side comparison helps identify:

• (frame or frameless) align=none is a valid use case, is not supported for mapframe, and I believe it should be. This is what this current ticket is about.
• (frameless) align=undefined does not behave the same for mapframe and images. I created T157640 to track this.

I've merged the content into the main page. I think it's an important enough question folks might have to include in the main documentation for the extension. And much easier to find than a little link in the "See also" section. 😄

I've also marked the new section up for translation.

https://www.mediawiki.org/wiki/Help:Extension:Kartographer#Rendering_options

In T157502#3023246, @CKoerner_WMF wrote:

I've merged the content into the main page. I think it's an important enough question folks might have to include in the main documentation for the extension. And much easier to find than a little link in the "See also" section. 😄

I've also marked the new section up for translation.

https://www.mediawiki.org/wiki/Help:Extension:Kartographer#Rendering_options

Thanks!
From your experience, how would you evaluate the need for align=none support? (in regards to T155601)

@JGirault Sorry for the delay in getting back to you. I asked around and a few concerns were raised if we didn't include align=none support.

1. You never know what communities can do when they have a way to be creative. Folks creating templates to work around the lack of the feature can be a pain down the road.
2. Will it cause accessibility issues for folks in any way by not having it? If it will, then we should add

"accessibility concerns" in the column for implementing the preference.

Another thought: Can editors use 2 extra linebreaks and left-align, to fake the same thing?