Quick script: Check ()[]{}

check_parentheses.py

MacroTab.title = "Check ()[]{}"

Glyphs.clearLog()
Glyphs.showMacroWindow()

# adapt as needed:
threshold = 1.0

font = Glyphs.font
print(font.familyName)

collectedLayers = []
for m in font.masters:
	mid = m.id
	for bracket in ("paren", "bracket", "brace"):
		leftGlyph = font.glyphs[bracket+"left"]
		rightGlyph = font.glyphs[bracket+"right"]
		if leftGlyph is None or rightGlyph is None:
			print(f"❌ master ‘{m.name}’: {bracket}left and {bracket}right do not exist.")
			continue
		leftLayer = leftGlyph.layers[mid]
		rightLayer = rightGlyph.layers[mid]
		leftOrigin = leftLayer.bounds.origin.y
		rightOrigin = rightLayer.bounds.origin.y
		leftTop = leftOrigin + leftLayer.bounds.size.height
		rightTop = rightOrigin + rightLayer.bounds.size.height
		originDiff = abs(leftOrigin-rightOrigin)
		topDiff = abs(leftTop-rightTop)
		if originDiff>=threshold or topDiff>=threshold:
			print(f"⚠️ master ‘{m.name}’: {bracket}left and {bracket}right not on same level: bottom {originDiff:.1f} off, top {topDiff:.1f} off.")
			collectedLayers.extend([leftLayer, rightLayer])

if not collectedLayers:
	Message(
		"All pairs of ()[]{} are on the same height.",
		title='🥳 Congrats',
		OKButton="Yippie",
		)
else:
	font.newTab(collectedLayers)
	print(f"✅ Found {int(len(collectedLayers)/2)} pairs. Opened in a new tab.")

Glyphs 3.x script for the Macro window.