compressed.md: might generate a huge amount of bytes

Make sure this is not a surprise

Closes #20028

diff --git a/docs/cmdline-opts/compressed.md b/docs/cmdline-opts/compressed.md
index 35bbab81396092edb9075202ab0b34f0d38ce2c9..a66cdff4fd865bc3083aca0e0047eb5028b70884 100644 (file)
--- a/docs/cmdline-opts/compressed.md
+++ b/docs/cmdline-opts/compressed.md
@@ -25,3 +25,6 @@ content is (still) compressed; while in fact it has already been decompressed.
 If this option is used and the server sends an unsupported encoding, curl
 reports an error. This is a request, not an order; the server may or may not
 deliver data compressed.
+
+**WARNING**: when decompressing data, even tiny transfers might be expanded
+and generate a huge amount of bytes.