For CSS property filters the chain size might even be 1, though not for ComputePostFilterExtents as that does SVG filters too I believe.
Bug 1520423 Comment 3 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
For CSS property filters the most common chain size might even be 1, though not for ComputePostFilterExtents as that does SVG filters too I believe.