Custom checkboxes not rendered

[nclm]

PDF files:

• https://dataetiskraad.dk/Media/637914000036298776/Vurderingsskema_Form_7.pdf
• https://dataetiskraad.dk/Media/637896027008136275/Konsekvensanalyse_Form_11.pdf

Configuration:

• Web browser and its version: Firefox 126.0b5
• Operating system and its version: macOS 14.3
• PDF.js version: unknown
• Is a browser extension: no?

Steps to reproduce the problem:

1. Open the PDFs above.
2. Go on pages after the cover.

What is the expected behavior?
Custom checkboxes should be rendered.

• Acrobat & Apple Preview:

• Chrome (works too but add blue overlays):

What went wrong?
Custom checkboxes are not rendered at all.

• Firefox:

[nclm]

Might be related to #12746 but not sure. Both PDFs are made with InDesign and have custom form elements, but the other is about buttons and they do appear (though not interactively), and this one is about checkboxes and they don‘t appear (but are interactive).

[momerjaved]

I would like to contribute and fix this issue, can you please assign it to me ? Also if you could tell which JS file(s) should I start to debug for the fix ?