Librsvg is a library to render SVG files using cairo as a rendering engine. For example, you can render SVG to in-memory RGBA surfaces, or to PDF streams.
Trivia: rsvg stands for "Resplendent SVG".
You can download the latest as well as previous releases from https://download.gnome.org/sources/librsvg.
You can ask questions about using librsvg in the Platform category in discourse.gnome.org.
You can also ask questions or report bugs in gitlab.gnome.org.
Be sure to read the development guide for instructions on how to contribute to librsvg's development.