Complex sentence: From April 2001 to April 2002 Collins acted as the Debian Project Leader, specialising on the UltraSPARC port and advocated for proactive security and testing policies.
Split into simpler sentences: From April 2001 to April 2002 Collins acted as the Debian Project Leader. During his tenor he specialised on the UltraSPARC port and advocated for proactive security and testing policies.