rlang has several options which may be set globally to control behavior. A brief description of each is given here. If any functions are referenced, refer to their documentation for additional details.
rlang_interactive: A logical value used by is_interactive(). This
can be set to TRUE to test interactive behavior in unit tests,
for example.
rlang_backtrace_on_error: A character string which controls whether
backtraces are displayed with error messages, and the level of
detail they print. See rlang_backtrace_on_error for the possible option values.
rlang_trace_format_srcrefs: A logical value used to control whether
srcrefs are printed as part of the backtrace.
rlang_trace_top_env: An environment which will be treated as the
top-level environment when printing traces. See trace_back()
for examples.