Complex sentence: MDB was developed on the 2.2 series Linux kernels in 1998 and released under the GNU Public License in 2000 since at the time, Linux did not have a kernel debugger.
Split into simpler sentences: MDB was developed on the 2.2 series Linux kernels in 1998 and released under the GNU Public License in 2000. At the time, Linux did not have a kernel debugger.