IPQ40xx Switch Config "Strangeness" (swconfig)

I just got vlan tagging on wan port in my EA8300 with OpenWRT 19.03 unomodified and this config:

config interface 'wan'
        option type 'bridge'
        option proto 'pppoe'
        option username 'ONHxxxx@vodafone'
        option password 'xxxx'
        option ipv6 '0'
        option ifname 'eth1.100'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '1'

config switch_vlan
        option device 'switch0'
        option vlan '1'
        option ports '0 1 2 3 4'
        option vid '1'

config switch_vlan
        option device 'switch0'
        option vlan '100'
        option vid '100'
        option ports '0t 5t'

got it thanks to this post by jeff:
https://forum.openwrt.org/t/solved-vlans-on-ipq40xx-alternative-config-for-fritzbox-4040/41832/4