Missing /MAAS/api/2.0/describe/ from the API doc

`maas login` and `maas refresh` CLI commands poke /MAAS/api/2.0/describe/ endpoint. However it's not documented in:
https://maas.io/docs/api

$ maas refresh -h
usage: maas refresh [-h]

Refresh the API descriptions of all profiles.

optional arguments:
  -h, --help show this help message and exit

This retrieves the latest version of the help information for each
profile. Use it to update your command-line client's information after
an upgrade to the MAAS server.

$ strace -e network maas refresh
socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC, IPPROTO_IP) = 3
bind(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_scope_id=0}, 28) = 0
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=140896, si_uid=1000, si_status=0, si_utime=0, si_stime=0} ---
socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC, IPPROTO_TCP) = 4
setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0
connect(4, {sa_family=AF_INET, sin_port=htons(80), sin_addr=inet_addr("192.168.12.19")}, 16) = 0
sendto(4, "GET /MAAS/api/2.0/describe/ HTTP"..., 136, 0, NULL, 0) = 136
recvfrom(4, "HTTP/1.1 200 OK\r\nServer: nginx/1"..., 8192, 0, NULL, NULL) = 8192
recvfrom(4, " String\\n\\n \", \"method\": \"POST\","..., 516096, 0, NULL, NULL) = 6049
recvfrom(4, " uuid: String\\n\\n \", \"method\": \""..., 507904, 0, NULL, NULL) = 28960
recvfrom(4, "am not_vlans: Optional. Only no"..., 483328, 0, NULL, NULL) = 37376
recvfrom(4, "Read license key\\n\\nRead a licen"..., 442368, 0, NULL, NULL) = 5792
recvfrom(4, " images. If no URL is provided, "..., 434176, 0, NULL, NULL) = 88600
recvfrom(4, "\", \"name\": \"read\", \"op\": null, \""..., 352256, 0, NULL, NULL) = 11584
recvfrom(4, "op\": \"add_tag\", \"restful\": false"..., 335872, 0, NULL, NULL) = 40544
recvfrom(4, "s\\n subnet\\n- **ranges**: the s"..., 294912, 0, NULL, NULL) = 33304
recvfrom(4, " to suit their redundancy or per"..., 262144, 0, NULL, NULL) = 24616
recvfrom(4, ":type subnet: String\\n\\n :param "..., 237568, 0, NULL, NULL) = 10136
recvfrom(4, " or not the given MAC address is"..., 229376, 0, NULL, NULL) = 33304
recvfrom(4, "n only one port (network\\n adap"..., 196608, 0, NULL, NULL) = 149144
recvfrom(4, "s_registered\", \"op\": \"is_registe"..., 49152, 0, NULL, NULL) = 49152
recvfrom(4, "/2.0/zones/{name}/\", \"uri\": \"htt"..., 8192, 0, NULL, NULL) = 766
getsockname(4, {sa_family=AF_INET, sin_port=htons(33546), sin_addr=inet_addr("10.0.8.190")}, [16]) = 0
getpeername(4, {sa_family=AF_INET, sin_port=htons(80), sin_addr=inet_addr("192.168.12.19")}, [16]) = 0
+++ exited with 0 +++