Licences
Interval reads your dive computer because other people did the hard part first. This page names their work.
libdivecomputer
Dive computer support by libdivecomputer, licensed under the GNU LGPL v2.1.
An open source library that speaks the transfer protocols of around 200 dive computers. The licence text and supported models are available at libdivecomputer.org. Interval uses a custom fork, with source available on GitHub.
Typefaces
Interval uses the system typeface on every platform it runs on. This website also uses your system’s interface typeface, with no third-party font requests.