The following bug has been logged on the website:
Bug reference: 14041
Logged by: Andras Jako
Email address: jako(dot)andras(at)eik(dot)bme(dot)hu
PostgreSQL version: 9.5.1
Operating system: FreeBSD
Description:
http://www.postgresql.org/docs/9.5/static/hot-standby.html says: "Users will
be able to tell whether their session is read-only by issuing SHOW
transaction_read_only."
http://www.postgresql.org/docs/9.5/static/sql-show.html says: "Available
parameters are documented in Chapter 18 and on the SET reference page."
But I can't find transaction_read_only mentioned nor in Chapter 18 nor on
the SET reference page.