Improve license description

Co-authored-by: Rickard Armiento <gitcommits@armiento.net>

CHANGELOG.md

@@ -21,7 +21,7 @@ In addition to the specification document itself, machine-readable schemas from
 - **Per entry/property metadata** ([#463](https://github.com/Materials-Consortia/OPTIMADE/pull/463)): Added a mechanism for providing metadata specific to a given entry or property.
 - **Files endpoint** ([#360](https://github.com/Materials-Consortia/OPTIMADE/pull/360)): The [`files` entry type](https://github.com/Materials-Consortia/OPTIMADE/blob/v1.2.0/optimade.rst#files-entries) has been added to provide a robust way of linking entries to arbitrary file-based data relevant to the entry, such as alternative crystal structure representation formats, input or output files from computational procedures, or experimental data files.
 - **Symmetry operation specification and space group fields** ([#480](https://github.com/Materials-Consortia/OPTIMADE/pull/480), [#405](https://github.com/Materials-Consortia/OPTIMADE/pull/405), [#464](https://github.com/Materials-Consortia/OPTIMADE/pull/464)): Several fields have been added to the `structures` entry type to fully describe symmetry. Symmetry operations can be provided explicitly in `space_group_symmetry_operations_xyz`, as well as space group specifications in various forms: `space_group_symbol_hall`, `space_group_symbol_hermann_mauguin`, `space_group_symbol_hermann_mauguin_extended`, `space_group_it_number`.
-- **Database licenses** ([#414](https://github.com/Materials-Consortia/OPTIMADE/pull/414)): Several fields have been added to programmatically describe the licensing status of data served by OPTIMADE APIs. A database-wide license can be provided as a set of [SPDX identifiers](https://spdx.org/licenses/) in `available_licenses`, with a related field `available_licenses_for_entries` specifying specifically which licenses are available for data contained within the database. The global field `license` can be used point to a human-readable license page (external or otherwise) that explains any caveats to the licensing arrangement.
+- **Database licenses** ([#414](https://github.com/Materials-Consortia/OPTIMADE/pull/414),[#497](https://github.com/Materials-Consortia/OPTIMADE/pull/497)): Several fields have been added to programmatically describe the licensing status of data served by OPTIMADE APIs. A database-wide license can be provided as a set of [SPDX identifiers](https://spdx.org/licenses/) in `available_licenses`, with a related field `available_licenses_for_entries` specifying specifically which licenses apply to individual entries and other non-substantial extracts from the database for cases where these differs from the database-wide licenses. The global field `license` can be used point to a human-readable license page (external or otherwise) that explains any caveats to the licensing arrangement.
 - **Database metadata field** ([#424](https://github.com/Materials-Consortia/OPTIMADE/pull/424)): Added an additional metadata field `database` for providing a human-readable description of a given database.
 - **Backoff time** ([#411](https://github.com/Materials-Consortia/OPTIMADE/pull/411)): Databases can now request ahead of time that clients apply a particular rate limit or back-off time via the `request_delay` metadata field.