Spends so much time, masquerading as a person with some semblance of personality and charm, they spend no actual time developing or doing anything significant with their life.
Usually a devloper is someone who produces little or no useful work. The issues they cause tend to cause significantly more work for others than productive work they themselves actually achieve.
Depending on experience level may be a junior devloper, and somehow eventually becomes a senior devloper, nobody knows why they got promoted or why they are still employed, but is often suspected that they have incriminating photographs of their boss.