MetaBench

MetaBench replaces the cramped core Custom Fields box with a panel built for
sites that actually have a lot of metadata.

• Search across both keys and values, with matches highlighted as you type.
• Filter by value type — text, number, long text, array, JSON or empty.
• Sort by key, by value size, or by raw database order.
• Edit in place, with a textarea for long values and JSON editing for
  serialised arrays.
• Rename, create and delete fields, each independently switchable.
• Works on posts and terms, on whichever post types and taxonomies you
  enable.
• Works in the block editor and the classic editor with no duplicated UI.

Permissions

For ordinary meta keys, every read and write goes through the per-key
capabilities that core derives from register_meta() auth callbacks. A user who
cannot edit such a field through core cannot edit it through MetaBench either.

Protected keys — those beginning with an underscore, where ACF, SEO plugins and
WooCommerce keep their data — work differently, and the difference is worth
understanding.

map_meta_cap() denies `edit_post_meta` on a protected key for *every* role,

including administrators, unless a plugin has registered an auth_..._meta_...
filter for that specific key. That blanket denial is aimed at untrusted REST and
XML-RPC callers, and it makes the core capability unusable as a gate for a
deliberate administrative tool.

MetaBench therefore gates protected keys separately. They are listed and
editable only when both:

1. “Show protected fields” is switched on in the settings, and
2. the user holds manage_options (filterable via
   metabench_protected_capability).

This is an intentional step past the core denial, kept as narrow and explicit as
possible. If you do not want that behaviour on your site, leave the setting off
— which is the default — and MetaBench will never touch a protected key.

Translations

MetaBench ships translated into German, Spanish, French, Italian, Japanese,
Dutch, Polish, Brazilian Portuguese, Russian, Ukrainian and Simplified Chinese,
covering all 119 translatable strings.

Every string the JavaScript panel displays is defined in PHP and handed to the
browser through wp_localize_script(), so the whole interface translates from a
single .po file with no JavaScript build step and no separate JSON language
packs.

To retranslate or add a locale, edit the .po file in languages/ with Poedit
or any gettext editor, then recompile:

wp i18n make-mo languages/ languages/
wp i18n make-php languages/

After changing translatable strings in the source, regenerate the template with
wp i18n make-pot . languages/metabench.pot –domain=metabench.

For developers

Filters:

• metabench_settings — the effective settings array.
• metabench_required_capability — the capability gating the panel.
• metabench_protected_capability — the capability gating protected keys.
• metabench_available_post_types / metabench_available_taxonomies — the
  choices offered on the settings screen.
• metabench_get_items — the rows returned for an object.
• metabench_validate_key — return a WP_Error to block a write.

REST routes, all under metabench/v1:

• GET /fields/<object_type>/<object_id>
• POST /fields/<object_type>/<object_id>
• POST /fields/<object_type>/<object_id>/<meta_id>
• DELETE /fields/<object_type>/<object_id>/<meta_id>