Missing definitions for parameters in MediaTrackCapabilties/MediaTrackConstraints?

In Sections 4.3.6 and 4.3.7, the various parameters that can be specified
are declared, but there is no text that defines their exact meaning. Are
they defined somewhere else, or did I just miss them?

e.g.
http://w3c.github.io/mediacapture-main/getusermedia.html#media-track-constraints
4.3.7.2 Dictionary MediaTrackConstraintSet
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-MediaTrackConstraintSet>
 MembersaspectRatio of type ConstrainDouble
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainDouble>
deviceId of type ConstrainDOMString
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainDOMString>
echoCancellation of type ConstrainBoolean
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainBoolean>
facingMode of type ConstrainDOMString
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainDOMString>
frameRate of type ConstrainDouble
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainDouble>
groupId of type ConstrainDOMString
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainDOMString>
height of type ConstrainLong
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainLong>
sampleRate of type ConstrainLong
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainLong>
sampleSize of type ConstrainLong
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainLong>
volume of type ConstrainDouble
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainDouble>
width of type ConstrainLong
<http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-ConstrainLong>