login/ticket_only_by_https is a SAP Parameter attribute which is used to control generate ticket that will only be sent via https information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
Specifies how the system sets the logon ticket, generated at logon using
http(s), in the browser.
1: Ticket is only sent by the browser during https connections.
0: Ticket is always sent.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.