Can't find twig filter

I am trying to trace “sylius_resolve_variant” twig filter in order to create my own customized filter
but I can’t find where it is written
this filter is used in SyliusShopBundle/views/Product/Show/_price.html.twig

can anyone help, please

It is declared in vendor/sylius/sylius/src/Sylius/Bundle/CoreBundle/Templating/Helper/VariantResolverHelper.php

src/Sylius/Bundle/CoreBundle/Resources/config/services/templating.xml

src/Sylius/Bundle/CoreBundle/Twig/VariantResolverExtension.php
src/Sylius/Bundle/CoreBundle/Templating/Helper/VariantResolverHelper.php