Projects that rely on BOSL exceptions should say that they do.

fixes #576

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

README.md

@@ -16,6 +16,14 @@ All code in this workspace is licensed under either of
 
 at your option.
 
+Downstream code forks should note that some (but not all) of these crates
+and components depend on the 'orchard' crate, which is licensed under the
+[Bootstrap Open Source License](https://github.com/zcash/orchard/blob/main/LICENSE-BOSL).
+An [exception](https://github.com/zcash/orchard/blob/main/COPYING) is
+provided that makes this a "permissive" license when used in Zcash or some
+of its chain forks. See the `README.md` files in subdirectories for which
+crates and components this applies to.
+
 ### Contribution
 
 Unless you explicitly state otherwise, any contribution intentionally

components/zcash_note_encryption/README.md

@@ -22,6 +22,13 @@ Licensed under either of
 
 at your option.
 
+Downstream code forks should note that 'zcash_note_encryption' depends on the
+'orchard' crate, which is licensed under the
+[Bootstrap Open Source License](https://github.com/zcash/orchard/blob/main/LICENSE-BOSL).
+An [exception](https://github.com/zcash/orchard/blob/main/COPYING) is
+provided that makes this a "permissive" license when used in Zcash or some
+of its chain forks.
+
 ### Contribution
 
 Unless you explicitly state otherwise, any contribution intentionally

zcash_client_backend/README.md

@@ -13,6 +13,13 @@ Licensed under either of
 
 at your option.
 
+Downstream code forks should note that 'zcash_client_backend' depends on the
+'orchard' crate, which is licensed under the
+[Bootstrap Open Source License](https://github.com/zcash/orchard/blob/main/LICENSE-BOSL).
+An [exception](https://github.com/zcash/orchard/blob/main/COPYING) is
+provided that makes this a "permissive" license when used in Zcash or some
+of its chain forks.
+
 ### Contribution
 
 Unless you explicitly state otherwise, any contribution intentionally

zcash_client_sqlite/README.md

@@ -24,6 +24,13 @@ Licensed under either of
 
 at your option.
 
+Downstream code forks should note that 'zcash_client_sqlite' depends on the
+'orchard' crate, which is licensed under the
+[Bootstrap Open Source License](https://github.com/zcash/orchard/blob/main/LICENSE-BOSL).
+An [exception](https://github.com/zcash/orchard/blob/main/COPYING) is
+provided that makes this a "permissive" license when used in Zcash or some
+of its chain forks.
+
 ### Contribution
 
 Unless you explicitly state otherwise, any contribution intentionally

zcash_extensions/README.md

@@ -0,0 +1,27 @@
+# zcash_extensions
+
+This library contains Rust code to support [Transparent Zcash Extensions](https://zips.z.cash/zip-0222).
+
+## License
+
+Licensed under either of
+
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+   http://www.apache.org/licenses/LICENSE-2.0)
+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+Downstream code forks should note that 'zcash_extensions' depends on the
+'orchard' crate, which is licensed under the
+[Bootstrap Open Source License](https://github.com/zcash/orchard/blob/main/LICENSE-BOSL).
+An [exception](https://github.com/zcash/orchard/blob/main/COPYING) is
+provided that makes this a "permissive" license when used in Zcash or some
+of its chain forks.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally
+submitted for inclusion in the work by you, as defined in the Apache-2.0
+license, shall be dual licensed as above, without any additional terms or
+conditions.

zcash_primitives/README.md

@@ -12,6 +12,13 @@ Licensed under either of
 
 at your option.
 
+Downstream code forks should note that 'zcash_primitives' depends on the
+'orchard' crate, which is licensed under the
+[Bootstrap Open Source License](https://github.com/zcash/orchard/blob/main/LICENSE-BOSL).
+An [exception](https://github.com/zcash/orchard/blob/main/COPYING) is
+provided that makes this a "permissive" license when used in Zcash or some
+of its chain forks.
+
 ### Contribution
 
 Unless you explicitly state otherwise, any contribution intentionally

zcash_proofs/README.md

@@ -13,6 +13,13 @@ Licensed under either of
 
 at your option.
 
+Downstream code forks should note that 'zcash_proofs' depends on the
+'orchard' crate, which is licensed under the
+[Bootstrap Open Source License](https://github.com/zcash/orchard/blob/main/LICENSE-BOSL).
+An [exception](https://github.com/zcash/orchard/blob/main/COPYING) is
+provided that makes this a "permissive" license when used in Zcash or some
+of its chain forks.
+
 ### Contribution
 
 Unless you explicitly state otherwise, any contribution intentionally