What is rp-pppoe-* packages used for?

Hi, I started to study how to build OpenWRT recently. I discovered there are three packages named rp-pppoe-common/server/relay. They are documented that "this open-source product is ideal for Linux users with\ a DSL "modem" whose Internet service provider uses PPPoE". In my understanding, this means I need this package to connect to my internet servicee provider, i.e. dail up.

However, it is written in wiki that

The packages ppp , kmod-pppoe and ppp-mod-pppoe must be installed to use PPPoE.

It seems I do not need rp-pppoe-* packages to dail up. I am really confused, can you please teach me these packages are used for what purpose? Thanks.