Hello I would like to know how BTCCollider works (https://github.com/JeanLucPons/BTCCollider)

how does he manage to find these 2 addresses:

Collision: 60 bits
Priv (WIF): p2pkh:L3K5y3LyKXUCmSmpptJrAG5w6o9r6YbfBQyWATV5gyhQ5dwq8moB
Priv (WIF): p2pkh:L3K5y3LyKXUCmSmpptJrAG5w6o9r6YbfBQxC9tihuggxfWGSwDY6
Add1: 12DgBEott9LiyPWspyZfY7K2EWv79498u2
Add2: 12DgBEott9LpupgZkw1fKKKK8pYPMoPatY6

is it random or does it start from one point to the next?