Another attempt at minimalism in software was Alan Kay's http://www.vpri.org/ , which aimed to develop an OS and applications in less than 20k lines of code [1]. It operated from 2001 to the start of this year. It is also associated with YC's harc [2].

[1] http://www.vpri.org/work/ifnct.htm

[2] https://harc.ycr.org/project/