Summary

This version holds window open a few centre meters while also holding it from closing.

I'd say it's not a security latch, it keeps our Mr Rascal Cat from jumping out the wrong windows, and stops the window slamming each time the wind blows. Yaye for that.

I've uploaded the Gcode for those who want to print it this second.
Prints fine at 1 shell, 10% infill and default speed.,,
Can print at fault high speed pritty well as seen in youtube,
https://www.youtube.com/watch?v=m0hAQzEHodU

A modification that might be worth considering is extruding the upper surface up so making it stronger if you have stronger wind than me.
NOTES about design,
fast print because of,,,
only two ends, rounded ends, rounded corners,width measured to match number of shells so in fills with shells at high speed without jitter.

Good luck.
Bye for now and be well from Will and Mr Data :) :]