Similarly, PDFs of articles in the PeerJ family of journals (e.g. [1]) have a progress bar symbol at the bottom-right of each page, which is also a nice feature

Similarly, PDFs of articles in the PeerJ family of journals (e.g. [1]) have a progress bar symbol at the bottom-right of each page, which is also a nice feature. [1]: https://peerj.com/articles/cs-103.pdf https://peerj.com/articles/cs-103.pdf