Yes, there’s a bit! Although it could be trimmed down a lot from what currently exists in PraxisLIVE due to how it’s evolved over time.
In performance, rarely. In live programming to build projects, teaching, talks, etc. all the time. Bear in mind it was built originally as a live development environment for building interactive projections and tools more than a performance tool. Stuff like this (from back when it was libGDX based rather than Processing). I was quite late to actually live coding as performance.