FRR introduced a local host-route protocol which is installed by kernel

[Cellebyte]

https://github.com/FRRouting/frr/blob/master/lib/route_types.txt

Linux represents them as

local 172.22.172.128 dev veth4d8a11d648c table local proto kernel scope host src 172.22.172.128

FRR says they look like this

show ip route vrf default local
Codes: K - kernel route, C - connected, L - local, S - static,
       R - RIP, O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric, t - Table-Direct,
       > - selected route, * - FIB route, q - queued, r - rejected, b - backup
       t - trapped, o - offload failure

L * 172.22.172.128/32 is directly connected, dum.cluster, 00:08:39