Display virtual adapters in network settings I've configured a host only adapter in Parallels Desktop. If I type ifconfig in the terminal that network adapter is listed in the output like:
...
bridge101: flags=8863&lt;UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST&gt; mtu 1500
    options=3&lt;RXCSUM,TXCSUM&gt;
    ether fa:ff:c2:xx:xx:xx 
    inet 192.168.12.98 netmask 0xffffffe0 broadcast 192.168.12.127
    inet6 fe80::c67:xxxx:xxxx:xxxx%bridge101 prefixlen 64 secured scopeid 0x14 
    Configuration:
        id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
        maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
        root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
        ipfilter disabled flags 0x0
    member: en11 flags=3&lt;LEARNING,DISCOVER&gt;
            ifmaxaddr 0 port 19 priority 0 path cost 0
    member: en12 flags=3&lt;LEARNING,DISCOVER&gt;
            ifmaxaddr 0 port 21 priority 0 path cost 0
    member: en13 flags=3&lt;LEARNING,DISCOVER&gt;
            ifmaxaddr 0 port 22 priority 0 path cost 0
    member: en14 flags=3&lt;LEARNING,DISCOVER&gt;
            ifmaxaddr 0 port 23 priority 0 path cost 0
    member: en16 flags=3&lt;LEARNING,DISCOVER&gt;
            ifmaxaddr 0 port 25 priority 0 path cost 0
    nd6 options=201&lt;PERFORMNUD,DAD&gt;
    media: autoselect
    status: active
    ...

Before I've upgraded to Big Sur, I was able to see those adapters also in the (visual) network settings of OSX. Now it is not listed there anymore. Is there a way to show them also in Big Sur?
Finally, I found the answer in the Parallels knowledge base (https://kb.parallels.com/125286):

Issue
After upgrading macOS to Big Sur, Connect Mac to this network
and Show in System Preferences options disappeared from Parallels
Desktop preferences &gt; Network..
Show in System Preferences option can not be selected so Host-Only
network cannot be found from macOS System Preferences &gt; Network.
Cause
These features are now hidden due to macOS Big Sur restrictions
(KEXT-less network mode): In macOS Big Sur Apple restricted usage of
kernel extensions and Parallels Desktop does not load them by default,
instead it uses macOS own built-in mechanism.
Workaround
Downgrade to Parallels Desktop 16.0.1 or earlier - make
sure the version is compatible with macOS Big Sur.