This is a list of custom things that our support team has found that helped some customers with their FD SSO config files to provide custom options to different Providers.
Passing custom query parameters to your OIDC Provider
oidcConfig.customParams = key: value, key2:v2
Allow unsigned tokens from your OIDC Provider
oidcConfig​.allowUnsignedIdTokens​=true
Custom SAML login URL
To modify the sign on url for SAML, access the provided metadata url. Usually you would just paste this URL into the fdsso.config file. Instead, copy the xml contents and paste it into a file that is located on the FlexDeploy server (not inside the apache-tomcat-flexdeploy folder). Then modify the file as needed. Reference this new file path from the fdsso.config file instead of the URL.
Change from using the email address to another unique identifier with SAML
To modify the username that is used in FlexDeploy, change the Unique User Identifier (Name ID) claim in the SAML provider. No changes are needed in FlexDeploy.