The title is there and filled out correctly; the apps just chose to omit it, which seems to be a pretty common thing - e.g. https://www.gyford.com/phil/writing/2020/04/10/web-share-api/

Note: I ignored the Replace the wikipedia-quote file name prefix with the filled template acceptance criteria.
I think the current filename is "fine" (although I'd perhaps prefer "share" over "quote" in there), and including anything arbitrary(ish) like the page title risks including weird characters/lengths/... in the filename which could introduce more issues & an additional round of testing to ensure it all works well in all environments it could be used in.

@JScherer-WMF @SherryYang-WMF When sharing, we feed the native share functionality 3 pieces of info: a title, text & the dialog image. These look something like this:

files: <the dialog image>
text: '"Whatever text I just selected, or the intro text"\n\nRead more: http://localhost:8080/wiki/My_page?wprov=shhu0#:~:text=Whatever%20text%20I%20just%20selected,%20or%20the%20intro%20text'
​title: 'Quote from "My_page" — Wikipedia'

The title seems to be ignored often, which begs the question: is there any important information in there that we may want to move to text instead?

could we change "Read more" to "Read more on Wikipedia"? only other thought is whether the title is used differently by screenreaders, would you know that?

Yes, we can change that text if we want.

Hard to tell - depends on whether/how the places things will be shared in implement and use this title/text.

In T423110#11840228, @matthiasmullie wrote:

@JScherer-WMF @SherryYang-WMF When sharing, we feed the native share functionality 3 pieces of info: a title, text & the dialog image. These look something like this:

files: <the dialog image>
text: '"Whatever text I just selected, or the intro text"\n\nRead more: http://localhost:8080/wiki/My_page?wprov=shhu0#:~:text=Whatever%20text%20I%20just%20selected,%20or%20the%20intro%20text'
​title: 'Quote from "My_page" — Wikipedia'

The title seems to be ignored often, which begs the question: is there any important information in there that we may want to move to text instead?

I think it's ok if the title is ignored sometimes or even often because the context of the link in the conversation will imply the title.

Change #1283684 had a related patch set uploaded (by Matthias Mullie; author: Matthias Mullie):

[mediawiki/extensions/ReaderExperiments@master] Turn share text into 'Read more on Wikipedia'

https://gerrit.wikimedia.org/r/1283684

Change #1283684 merged by jenkins-bot:

[mediawiki/extensions/ReaderExperiments@master] Turn share text into 'Read more on Wikipedia'

https://gerrit.wikimedia.org/r/1283684

Looks clean, and will stay compatible for any previously-localized messages that don't get updated. (If and when they do get updated, they will automatically pick up the new parameter for the sitename config var.) +2'd and merged.

The two cards are different - the share article card, i.e. when the article share button (id=ca-re-share is clicked) , doesn't display an article title:
wikipedia-quote-sun.png

When the share highlight card (some text is selected) is shared, the article title is displayed:
wikipedia-quote-sun.png (the same file name)

Is it expected behavior?

In T423110#11857529, @SherryYang-WMF wrote:

could we change "Read more" to "Read more on Wikipedia"? only other thought is whether the title is used differently by screenreaders, would you know that?

@SherryYang-WMF - the screen readers read only the controls on a share card, i.e. the close button and the link/download icons buttons, and the share button.

@Etonkovidova yes, that's expected behavior.
Article share shows the full wiki wordmark logo ("Wikipedia", or in this case "W/beta") and no title.
Selection share shows the small wordmark ("W") and the article title.
The thinking is that the summary text for article share will likely already include the page's subkect (where it will be bolded), but it's likely to be missing in selections, and explicitly adding it there adds the missing context.