[keycloak-user] securing 3rd party non-OIDC/SAML applications

Reading through the documentation, I'm not sure if I'm understanding the security proxy correctly. We have a few applications that use either Apache htaccess or form type authentication built into the application. Since we don't always have access the source code to add OIDC or SAML capability, I thought the Keycloak security proxy might be a possible solution. I'm wondering if it can work with just anything or does the app have to have at least minimal OIDC or SAML capability? Are there any good examples anywhere? Steve