You can use the following command:
mgmt_cli -r true show access-rulebase name "layer name" | grep -B 1 access-section
https://sc1.checkpoint.com/documents/latest/APIs/#cli/show-access-rulebase~v1.9%20
It will show all the Section Titles in the Layer with the name of each section (one line before the grep). You can also view additional lines after the output using -A <value>
An example of the output from my lab:
[Expert@gw-a30d15:0]# mgmt_cli -r true show access-rulebase name "NEW1 Network" | grep -B 1 access-section
name: "Test Section 1"
type: "access-section"
--
name: "Test Section 2"
type: "access-section"