Couldn't find the language specification anywhere, it basically the Nix source? The repo's README refers to the Nix manual, but it seems incomplete. For example
simplenlg
chrome-api
desiredcapabilities
hardware-port
spring-data-hadoop
vuetifyjs3
amp-access
angular-material-7
javacc
sweetalert2
monitoring
android-testing
html2canvas
wcf-configuration
cardview
linq-to-entities
parallel-arrays
icefaces
scala-version-cross-build
logging
pymesh
jetbrains-rider
porter-stemmer
dmesg
azureportal
phpdebugbar
marker-interfaces
scoping
shiny
reactcsstransitiongroup