Sioyek

Sioyek is a PDF viewer built for reading long technical documents such as textbooks and research papers. It runs on the desktop and is designed around fast keyboard-driven navigation rather than editing, so you can move through dense material quickly.

Smart Jump lets you follow references to figures and bibliography entries even when the document has no embedded links, and an overview window shows the target without losing your place. Marks and bookmarks let you jump back to saved locations, and portals can mirror a referenced figure in a second window.

You can highlight and search text, customize key bindings and preferences, and install it from official packages for Windows, macOS, and Linux or via a Homebrew Cask.