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