  Cosmic strings radiate detectable gravitational waves in models featuring
high-scale symmetry breaking, e.g., high-scale leptogenesis. In this Letter,
for the first time, we show that different flavored regimes of high-scale
leptogenesis can be tested distinctly with the spectral features in cosmic
string-radiated gravitational waves. This is possible if the scalar field that
makes right-handed neutrinos massive is feebly coupled to the Standard Model
Higgs. Each flavored regime, sensitive to low-energy neutrino experiments,
leaves a marked imprint on the gravitational waves spectrum. A three-flavor and
a two-flavor regime could be probed by a characteristic fall-off of the
gravitational wave spectrum at the LISA-DECIGO-ET frequency bands with
preceding scale-invariant amplitudes bounded from above and below. We present
Gravitational Waves windows for Flavored Regimes of Leptogenesis (GWFRL)
falsifiable in the upcoming experiments.
