We have followed certain agile practices – e.g. automated tests, some pair programming, no big up front design, incremental / iterative development, etc.
We do not follow a specific approach like XP or Scrum, although we do use some of their ideas.
The development of suneido itself (i.e. the C++ and Java code) has mostly been done by one person (me). The standard library (stdlib) has been worked on by more people.
Does that answer your question?