Curiefense is implemented in Rust, so Rust's default regex is a natural fit for the project. Therefore, Regex expressions throughout Curiefense should be compliance with this library.
There is one exception to this: Content Filter Rules (also known as signatures). Here Curiefense uses Hyperscan: a high-performance open source library that allows simultaneous matching of large numbers of regular expressions across streams of data.
Anywhere in the UI where Regex is acceptable, the icon of code </> is added to the left of the input box.