
Blender manual:
The new option Keep Bind Info checks each bone for having two arrays:
    rest_mat  an array of 16 floats which represent the bones original rest-pose matrix.
    bind_mat  an array of 16 floats which represent the bones original bind-pose matrix.
    Those two arrays can later be used when you want to export the rig again and be sure the original rest pose/bind pose combination must be used.


https://wiki.blender.org/wiki/Dev:Ref/Release_Notes/2.79/Add-ons
 
https://lists.blender.org/pipermail/bf-blender-cvs/2016-May/086767.html

https://developer.blender.org/T38660

https://developer.blender.org/T50412      2017
(Gaia Clary)
Back in 2.70 this issue was solved in a very ugly way:

we added a custom transformation to each bone which contains a scale, a rotation and a translation:

restpose_scale_x (default = 1.0)
restpose_scale_y (default = 1.0)
restpose_scale_z (default = 1.0)

restpose_rot_x (default = 0.0)
restpose_rot_y (default = 0.0)
restpose_rot_z (default = 0.0)

restpose_loc_x (default = 0.0)
restpose_loc_y (default = 0.0)
restpose_loc_z (default = 0.0)
...
So i proceed as follows now:

    I add the code for creating the custom properties to the Collada importer
    I add an option to the importer to "import bind pose info"
    I also add a new option to the exporter "use custom bind pose"

https://developer.blender.org/T69400







https://community.secondlife.com/forums/topic/324977-liquid-democracy-new-free-and-open-source-kit-prototype-to-rig-fitted-mesh/?tab=comments#comment-1092118

https://community.secondlife.com/forums/topic/337070-importing-a-rigged-mesh-from-maya-to-blender/

https://community.secondlife.com/forums/topic/350794-collada-and-blender-leaf-bones-differences-deform-bones-and-rest-pose/

https://community.secondlife.com/forums/topic/440243-avatar-animation-along-wrong-axes/

https://community.secondlife.com/forums/topic/430911-bones-names/

