Type Default Option: -utf8 sets to true
string see below x3270 c3270 wc3270 s3270 b3270

If the resource is true, returned text is encoded as UTF-8, and input text (such as keymaps) are interpreted as UTF-8. On Windows, it overrides the value of the localCp resource.

If set to false, the local text encoding is platform-specific.

The default is true in b3270 (new in 4.2), false in all other emulators.