Browsers can display PDFs natively, but how can they be embedded in a site?
PDF
https://www.drupal.org/project/pdf
Install PDF.js w/ composer.
D11 RBTC.
Display settings.
5200 8x+ users
PDF Reader
https://www.drupal.org/project/pdf_reader
Lists outdated viewers.
1700 8x+ users.
PDF To Canvas File Field Formatter
https://www.drupal.org/project/pdf_to_canvas
Render PDF as canvas element.
Loads pdf.js pdf.worker.js from cdn.
D11 compatibility.
34 users, but some growth.
PDF Slideshow
https://www.drupal.org/project/pdf_slideshow
Render PDF file fields as image slideshow.
50 users.
ViewerJS Formatter
https://www.drupal.org/project/viewerjs_formatter
ViewerJS integragion - is this outdated?.
14 users.
Embedded Google Docs Viewer
https://www.drupal.org/project/gdoc_field
Uses Google Docs API, which doesn't work locally and needs public access to the PDF.
Document Previewer
https://www.drupal.org/project/document_preview
Google Docs API.
PDF worked for me, and seems like it does what I was looking for.