The short version

Everything here is free and open, just under different licenses depending on what it is:

The complete, machine-readable licensing metadata lives in the source repository, which follows the REUSE specification. Full license texts are in its LICENSES/ directory.

Third-party bits

This site bundles libraries and fonts made by other lovely people:

ComponentLicenseCopyright
jQueryMITOpenJS Foundation and other contributors
jQuery TerminalMITJakub T. Jankiewicz
PrismJSMITLea Verou and PrismJS contributors
elasticlunrMITOliver Nightingale and Wei Song
KeyboardEvent.key polyfillMITChristopher Van Wiemeersch and contributors
WebTUIMITWebTUI
0xProto (font)OFL-1.10xType
Symbols Nerd FontMITNerd Fonts contributors

The CSS reset is based on Andy Bell's modern CSS reset.