See
https://docs.wildfly.org/25/WildFly_Elytron_Security.html#Elytron_and_Java_Authentication_SPI_for_Containers-JASPI

there is NO chapter 8 in the index on the left. There is a
chapter 7 and chapter 9. Section 8 is presented within chapter 9.
In addition there is no chapter 10.  Chapter 11 contains section 10 content.

The source for the Elytron_and_Java_Authentication_SPI_for_Containers-JASPI chapter can be found here:
https://github.com/wildfly/wildfly/blob/main/docs/src/main/asciidoc/_elytron/Elytron_and_Java_Authentication_SPI_for_Containers-JASPI.adoc

The source for other chapters can be found here:
https://github.com/wildfly/wildfly/tree/main/docs/src/main/asciidoc