Jenkins is a widely used open-source automation and CI system - https://www.jenkins.io/
Status
Jenkins Agents are pure java program and works out of the box on windows on arm machine.
Jenkins Controllers are not yet available for Windows on Arm. The main missing bits are:
Native Code
Inside a jenkins .war, we can find .jar. By unzipping all this, we can identify those dlls:
./com/sun/jna/win32-aarch64/jnidispatch.dll ./com/sun/jna/win32-x86/jnidispatch.dll ./com/sun/jna/win32-x86-64/jnidispatch.dll ./META-INF/native/windows64/jansi.dll ./META-INF/native/windows32/jansi.dll ./winp.dll ./winp.x64.dll
jansi/winp would need work to have native arm64 versions.