Where does Network Manager get the interface address from?

[Chris Green]

I have the following configuration file in NetworkManager/system-connections 

    [connection]
    id=WiFi Hotspot
    uuid=80fe068d-c8b2-491c-828a-155b41c93057
    type=wifi
    autoconnect=false
    permissions=
    timestamp=1581936051

    [wifi]
    mac-address-blacklist=
    mode=ap
    seen-bssids=00:28:F8:3D:3B:AA;
    ssid=T470 Hotspot

    [wifi-security]
    key-mgmt=wpa-psk
    psk=brzmi074

    [ipv4]
    dns-search=
    method=shared

    [ipv6]
    addr-gen-mode=stable-privacy
    dns-search=
    ip6-privacy=0
    method=shared

    [proxy]

When I set my WiFi connection to use this it always give an inet
address of 10.42.0.1, where does it get this from?  I can't find
anything in /etc that seems to have this address.

Presumably I need to set up a DHCP server too to provide any clients
with an address.

-- 
Chris Green