Virvla uses these open-source components. Thank you to their authors.

PDF.js (pdfjs-dist) — Apache License 2.0 — https://github.com/mozilla/pdf.js
pdf-lib — MIT License — https://github.com/Hopding/pdf-lib
Mediabunny — Mozilla Public License 2.0 — https://github.com/Vanilagy/mediabunny
@mediabunny/mp3-encoder — Mozilla Public License 2.0; includes LAME (LGPL-2.0) — https://lame.sourceforge.io
heic-to — LGPL-3.0; includes libheif (LGPL-3.0) and libde265 (LGPL-3.0)
    Source: https://github.com/hoppergee/heic-to , https://github.com/strukturag/libheif , https://github.com/strukturag/libde265
    These libraries are loaded as separate files; you may replace them with your own builds.
face-api (@vladmandic/face-api) — MIT License; includes TensorFlow.js (Apache License 2.0)
gifenc — MIT License — https://github.com/mattdesl/gifenc
JSZip — MIT License — https://github.com/Stuk/jszip
Familjen Grotesk — SIL Open Font License 1.1
Astro — MIT License

Sample photo (the red barn, /img/barn.* and /sample/IMG_4021.HEIC) — from the Kodak Lossless True
Color Image Suite (kodim22), released by the Eastman Kodak Company for unrestricted usage.