Liquid is an open-source template language created by Shopify and written in Ruby. Full documentation on the Liquid language can be found at Shopify's GitHub pages. Cyotek Colour Palette Editor uses an implementation of Liquid called DotLiquid, some variations between this and the official Shopify Liquid may be present.
Cyotek Colour Palette Editor includes a number of non-standard filters to aid with creating templates.