In short: this is meant to be circuit simulation of simple sawtooth-waveform VCO in LTspice.
Links:
https://kassu2000.blogspot.com/2015/12/vco-part-1-core.html (I based its design on this article)
https://modwiggler.com/forum/viewtopic.php?t=193431 (some thread on electronic music forum regarding very similar design)