user-mode-linux - 4.19-1um-1+deb10u1+b1 main

User-mode Linux (UML) is a port of the Linux kernel to its own system
call interface. It provides a kind of virtual machine, which runs
Linux as a user process under another Linux kernel. This is useful
for kernel development, sandboxes, jails, experimentation, and many
other things.
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This package contains the kernel itself, as an executable program,
and the associated kernel modules.