Please note there is now an official build of JAGS for UCRT, it is versioned
4.3.1 and it is available from

https://sourceforge.net/projects/mcmc-jags/files/JAGS/4.x/Windows/JAGS-4.3.1.exe

The official build of JAGS 4.3.0 is only of MSVCRT.  Please use the official
build with R >= 4.2 to avoid potential confusion.

For reference, these are resources to build JAGS 4.3.0 for UCRT, which were
needed for using JAGS with R packages in the UCRT builds of R before the
official build became ready. The resulting installer
executable is available at 
https://www.r-project.org/nosvn/winutf8/ucrt3/extra/jags/