I have been testing today and logging results here:
https://docs.google.com/spreadsheets/d/1CdHhFDoTOfbLDCuwVViAWSFlduNE88h3mCbSKIRbKcs/edit?usp=sharing

I'll keep adding details as I go. So far, no failures that are not known issues (Example: background colors on tables https://www.mediawiki.org/wiki/Reading/Web/Projects/Print_Styles#Limitations).

Found some kerning issues also listed in this ticket - T178665

Browser Print	PDF

https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Least weasel/letter/desktop

Kerning issues look similar across desktop style PDFs. The kerning issues look less severe on mobile styles

Desktop Letter	Desktop A4	Desktop Legal
Mobile Letter	Mobile A4	Mobile Legal

https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Barack Obama/letter/desktop

https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Barack Obama/a4/desktop

https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Barack Obama/legal/desktop

https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Barack Obama/letter/mobile

https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Barack Obama/a4/mobile

https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Barack Obama/legal/mobile

We may want a better treatment for audio files in PDFs -

Here is an example of a video file. There is a link to the video that works -

There are no 'featured' or 'protected' icons present. Here is the Barack Obama article which is both.

There are also two 'series' infoboxes in the article which do not appear in the PDF.

Website	PDF

Note the 2 series infoboxes appear under the main article infobox.

This article has an odd issue with the infobox. In this case the infobox does not start on page 1. So far this is the only article I found that displays this issue.
https://zh.wikipedia.org/wiki/%E9%A9%AC%E9%87%8C%E6%98%82%E5%86%9B%E4%BA%8B%E5%AD%A6%E9%99%A2
https://proton-beta.wmflabs.org/zh.wikipedia.org/v1/pdf/马里昂军事学院/a4/desktop

This article has some issues with the references section. I noticed on the article itself that the reference section has it's own scroll bar.
https://ar.wikipedia.org/wiki/%D9%82%D9%86%D8%A7%D8%A9_%D8%A7%D9%84%D8%B3%D9%88%D9%8A%D8%B3
https://proton-beta.wmflabs.org/ar.wikipedia.org/v1/pdf/قناة السويس/legal/desktop

The 1st image in this article has a frame around it with a blue link in the image notes. In PDF form, only the top of the frame appears and the link is not blue.
https://ko.wikipedia.org/wiki/%ED%97%8C%EB%B2%95
https://proton-beta.wmflabs.org/ko.wikipedia.org/v1/pdf/헌법/letter/desktop

Webite	PDF

Also appears on mobile PDF

This article has 2 collapsed tables at the bottom. The text is a bit scrambled near the top of those tables in the PDF. Also, the URLs in this section are a bit wonky.
https://bg.wikipedia.org/wiki/%D0%91%D1%80%D0%B0%D0%B7%D0%B8%D0%BB%D0%B8%D1%8F_%E2%80%93_%D0%93%D0%B5%D1%80%D0%BC%D0%B0%D0%BD%D0%B8%D1%8F_%28%D0%A1%D0%B2%D0%B5%D1%82%D0%BE%D0%B2%D0%BD%D0%BE_%D0%BF%D1%8A%D1%80%D0%B2%D0%B5%D0%BD%D1%81%D1%82%D0%B2%D0%BE_%D0%BF%D0%BE_%D1%84%D1%83%D1%82%D0%B1%D0%BE%D0%BB_2014%29
https://proton-beta.wmflabs.org/bg.wikipedia.org/v1/pdf/Бразилия – Германия (Световно първенство по футбол 2014)/letter/desktop

Website	PDF

I am seeing similar problems with these articles.
https://sl.wikipedia.org/wiki/Mura
https://proton-beta.wmflabs.org/sl.wikipedia.org/v1/pdf/Mura/legal/desktop

https://hi.wikipedia.org/wiki/%E0%A4%AD%E0%A5%82%E0%A4%B8%E0%A5%8D%E0%A4%A5%E0%A4%BF%E0%A4%B0_%E0%A4%89%E0%A4%AA%E0%A4%97%E0%A5%8D%E0%A4%B0%E0%A4%B9_%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%95%E0%A5%8D%E0%A4%B7%E0%A5%87%E0%A4%AA%E0%A4%A3_%E0%A4%AF%E0%A4%BE%E0%A4%A8_%E0%A4%B8%E0%A4%82%E0%A4%B8%E0%A5%8D%E0%A4%95%E0%A4%B0%E0%A4%A3_3
https://proton-beta.wmflabs.org/hi.wikipedia.org/v1/pdf/भूस्थिर उपग्रह प्रक्षेपण यान संस्करण 3/legal/desktop

This PDF is missing a few items when compared to the article on the website. There is a small box below the infobox that does not appear in the PDF. There are also a number of collapsed tables at the bottom of the article that do not appear in the PDF.
https://ur.wikipedia.org/wiki/%D8%A7%D8%B1%D8%AF%D9%88
https://proton-beta.wmflabs.org/ur.wikipedia.org/v1/pdf/اردو/a4/desktop

Website	PDF

This article also has tables at the bottom that do not appear in the PDF.
https://bn.wikipedia.org/wiki/%E0%A6%AD%E0%A6%BE%E0%A6%B0%E0%A6%A4
https://proton-beta.wmflabs.org/bn.wikipedia.org/v1/pdf/ভারত/letter/desktop

Website	PDF

This article has a wide table containing images. The table is a bit cut off on the right end in the PDF.
https://ka.wikipedia.org/wiki/%E1%83%92%E1%83%A0%E1%83%98%E1%83%A4%E1%83%98%E1%83%9C%E1%83%94%E1%83%91%E1%83%98
https://proton-beta.wmflabs.org/ka.wikipedia.org/v1/pdf/გრიფინები/a4/desktop

website	PDF

The mobile version of the PDF shows some issues on the Mathematics article. The right edge is cutoff
https://en.wikipedia.org/wiki/Mathematics
https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Mathematics/a4/mobile

Mobile	PDF

The Barack Obama and other articles produce very small images in PDF
https://en.m.wikipedia.org/wiki/Barack_Obama
https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Barack Obama/a4/mobile

Mobile	PDF

Other examples.

Found an issue with the mobile PDF of this site. The image is overlapping the infobox.
https://bg.m.wikipedia.org/wiki/%D0%91%D1%80%D0%B0%D0%B7%D0%B8%D0%BB%D0%B8%D1%8F_%E2%80%93_%D0%93%D0%B5%D1%80%D0%BC%D0%B0%D0%BD%D0%B8%D1%8F_(%D0%A1%D0%B2%D0%B5%D1%82%D0%BE%D0%B2%D0%BD%D0%BE_%D0%BF%D1%8A%D1%80%D0%B2%D0%B5%D0%BD%D1%81%D1%82%D0%B2%D0%BE_%D0%BF%D0%BE_%D1%84%D1%83%D1%82%D0%B1%D0%BE%D0%BB_2014)

https://proton-beta.wmflabs.org/bg.wikipedia.org/v1/pdf/Бразилия_–_Германия_%28Световно_първенство_по_футбол_2014%29/a4/mobile

Found this odd image placement in the mobile PDF of this article.
https://bn.m.wikipedia.org/wiki/%E0%A6%AD%E0%A6%BE%E0%A6%B0%E0%A6%A4

https://proton-beta.wmflabs.org/bn.wikipedia.org/v1/pdf/ভারত/a4/mobile

Mobile site	PDF

@ABorbaWMF If you missed it, this may be relevant – I'd assumed in writing the comment (after the issue had been closed) that the renderer was going to be deployed soon, rather than that it was still being tested. Summary: Images are not aligned correctly; images appear to be distorted; the inline CSS colours are gone.

In T178664#4248299, @Jc86035 wrote:

The image – if from Chromium – seems a bit problematic. One of the images is still clearly incorrectly aligned, the one in the Lai King row. This is worrying, because it might mean that the new software is incorrectly rounding the image widths. (The gap between that image and the other images in the row is an empty table cell with a set width.) Several of the images (the corner pieces for the 45° tracks) did not render at all, and many of the ones which did render appear to be quite distorted (the circles should be round, and the curves in the second-last row should be smooth). I can't tell why.

Obviously, these are not problems for most images, but it would be nice if they could be fixed (if they're problems with the renderer). These diagrams are used on more than ten thousand pages across WMF wikis.

In addition, the colours being stripped makes the interchange boxes useless, and the background colour being stripped makes the fade overlays look incorrect because IIRC they are supposed to match #f9f9f9 (the old MediaWiki table background colour). However, this is more of a problem with whatever CSS is being used.

@ABorbaWMF - could you take a look at T178664#4248299 again using the chromium renderer? Could also be related to https://bugs.chromium.org/p/chromium/issues/detail?id=741049

Reviewed QA issues with @pmiazga:

• Kerning - reopened T178665: [Spike, 8hrs] Grave kerning issues and spacing issues in PDFs generated by Chromium (and previous Electron) via "Download as PDF" and pulled into the sprint
• Audio and video - @ovasileva to set up a new task for having placeholders, doesn’t inject media player - no JS available
• T195991#4259699 - fix by removing max height - @pmiazga to create new ticket, set as low priority
• Link underlining - no underlining on desktop - @ovasileva to set up a separate card for Alex to review
• T195991#4259706 - nav boxes not hidden properly - @pmiazga to create a ticket
• T195991#4261604 - @pmiazga to create spike on how to handle wide tables in PDF, add issues seen in https://en.wikipedia.org/wiki/Mathematics as well

• T195991#4259699 - fix by removing max height - @pmiazga to create new ticket, set as low priority - DONE: T197032
• T195991#4261604 - @pmiazga to create spike on how to handle wide tables in PDF, add issues seen in https://en.wikipedia.org/wiki/Mathematics as well - DONE: T197034
• T195991#4259706 - nav boxes not hidden properly - @pmiazga to create a ticket - DONE: T197035

@ovasileva Using the PDF renderer for the Tsuen Wan Line article.
https://en.wikipedia.org/wiki/Tsuen_Wan_line
https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Tsuen_Wan_line/letter/mobile

Chromium PDF has some issues with the quality of images, usually, images are printed in low-quality images. Probably Chromium has to fix it first:

• https://bugs.chromium.org/p/chromium/issues/detail?id=838497
• https://bugs.chromium.org/p/chromium/issues/detail?id=741049

I can investigate that topic, but I'm not sure if there is anything we can do right now.

In T195991#4278372, @pmiazga wrote:

Chromium PDF has some issues with the quality of images, usually, images are printed in low-quality images. Probably Chromium has to fix it first:

• https://bugs.chromium.org/p/chromium/issues/detail?id=838497
• https://bugs.chromium.org/p/chromium/issues/detail?id=741049

I can investigate that topic, but I'm not sure if there is anything we can do right now.

Sounds good - seems like we might just want to keep the original task open to note it's still an issue .

In T195991#4277569, @ABorbaWMF wrote:

@ovasileva Using the PDF renderer for the Tsuen Wan Line article.
https://en.wikipedia.org/wiki/Tsuen_Wan_line
https://proton-beta.wmflabs.org/en.wikipedia.org/v1/pdf/Tsuen_Wan_line/letter/mobile

This PDF, rendered in Preview.app on macOS, has oversized text which breaks the rows of the diagram table (the images should appear to be continuous). Inexplicably, the images are still rendered at their normal size. Changing the font size is probably not good, since many pages have objects with dimensions specified in pixels.