Siege

Siege damage converts surviving siege capacity into building-level destruction after a successful attack. Source

Evidence status — confirmed: Unless noted otherwise, mechanics are verified against the installed patch 11.73 guide.

raw siege = Σ(count × siege stat × carrier effect)
survival scale = max(0.2, surviving siege / initial siege)
final budget = raw siege × fleet siege multiplier × survival scale

Stasis Bastion multiplies that budget by 0.75. Each destroyed building level consumes 40% of that level’s total build cost. With no selected target, siege hits the highest-level building. A non-spawn base disappears when every building reaches zero.