angle limit for ankle

[jjehl]

Is it normal to have opposite angle limit for r and l ankle ?
r_ankle_y": {
"offset": 0.0,
"type": "MX-28",
"id": 25,
"angle_limit": [
-45,
45
],
"orientation": "indirect"
angle_limit is [45,-45] for r_ankle and [-45,45] for l_ankle, something strange because not the knees have the same limit angles for left and right.