apply_filters_deprecated( 'tag_rewrite_rules', string[] $rules )
This hook has been deprecated. Use ‘post_tag_rewrite_rules’ instead.
Filters rewrite rules used specifically for Tags.
Parameters
- $rules
-  (string[]) Array of rewrite rules generated for tags, keyed by their regex pattern. 
Source
Changelog
| Version | Description | 
|---|---|
| 3.1.0 | Use 'post_tag_rewrite_rules' instead. | 
| 2.3.0 | Introduced. | 
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Licensed under the GNU GPLv2+ License.
    https://developer.wordpress.org/reference/hooks/tag_rewrite_rules