Resources and materials to get yourself started with open source
Spelling, grammar and style checking on LaTeX documents
The universal markup converter
A PDF Reader in JavaScript
An ebook reader application supporting PDF, DjVu, EPUB, FB2, etc.
OCRmyPDF adds an OCR text layer to scanned PDF files
Open source PDF editor
WebDriver for Firefox
open source Java library for creating and editing PDF files
Make Zotero effective for us LaTeX holdouts
A simple interface for working with TeX documents
Windows/macOS/Linux binaries and installation methods of TinyTeX
A JSON viewer plugin for Notepad++
An open source RDP server
HTML, CSS and JS framework for developing responsive websites and apps
the MiKTeX source code
HTML5 client solution for generating PDFs
Lightweight, powerful flow control component
PDFCraft is a free, privacy-focused PDF toolkit
Simple extensive tar-like archive format with indexing
Edit PDF files with Nano Banana
A simple tool for reading in poorly redacted documents
JSON that's part of C++
A LaTeX class for producing presentations and slides
The lxml XML toolkit for Python