diff --git a/man/ebuild.5 b/man/ebuild.5
index 2652f89..0d5e448 100644
--- a/man/ebuild.5
+++ b/man/ebuild.5
@@ -349,6 +349,15 @@ Without it, fBemergefR defaults to install only runtime dependencies (i.e.
.PP
See section fBVARIABLESfR for more information about the fBDEPENDfR,
fBRDEPENDfR and fBHDEPENDfR variables.
+.TP
+.B The targetroot USE flag
+For EAPIs that support the "fItargetrootfR" USE flag, that flag is
+automatically enabled by the package manager if fIhostfR and fItargetfR
+system are not the same, i.e. if the fBROOTfR is not "fI/fR".
+This is necessary where the package to be built needs an executable copy of
+itself during the build process.
+A known example is dev-lang/python, which needs to run a Python interpreter
+during compilation.