You will need the parameters below in your sqlnet.ora file.
See more details here. https://docs.oracle.com/cd/B28359_01/network.111/b28530/asokerb.htm#i1006294
I think, you misunderstand my question.
I have sqldeveloper running connection to database with "Kerberos authentication" check box on; it is working perfect without setting any additional parameters in sqlnet.ora on client machine. I know that sqldeveloper generated some parameters in sqlnet on client machine when "Kerberos authentication" check box turn on. I'd like to know what parameters sqldeveloper automatically added when Kerberos authentication checked? Also maybe sqldeveloper has additional jar for these connection, I can use them in oracle forms startup.