Jon Henshaw

Coywolf Code Block Enhancer extends the built-in <code>core/code</code> block. In the editor 
it adds a “Code language” dropdown to the block sidebar; on the front end 
it highlights the code with Prism.js using a custom token palette, prints 
the language name as a small label on the block, and pins a 
copy-to-clipboard button to the top-right corner.
<ul>
<li>Adds a “Code language” dropdown to the core Code block’s sidebar. A 
baseline of 9 languages (Bash, CSS, HTML/Markup, JavaScript, JSON, 
PHP, Python, SQL, YAML) is always loaded; an additional 40 grammars 
can be toggled on via Language packs in Tools → Code Blocks 
(Web/App dev — TypeScript, JSX/TSX, SCSS, Sass, Less, GraphQL — is 
enabled by default).</li>
<li>Highlights code on the front end with Prism.js. Pick from 45 bundled 
themes — the 8 stock Prism themes (Prism Default, Coy, Dark, Funky, 
Okaidia, Solarized Light, Tomorrow Night, Twilight) plus 37 community 
themes from PrismJS/prism-themes (a11y Dark, Atom Dark, Dracula, 
Nord, One Dark, Night Owl, Synthwave ’84, Gruvbox, Material, VS Code 
Dark+, and more) — or the bundled Default palette (selected on 
first install).</li>
<li>Adds a small language label in the top-left of each highlighted block 
(only when a language is set).</li>
<li>Adds an accessible copy-to-clipboard button — <code>aria-label</code>, a polite 
status region that announces “Copied to clipboard,” and a visible “✓” 
state for two seconds after a successful copy. Falls back to 
 document.execCommand(‘copy’) on non-HTTPS or older browsers.</li>
<li>Assets load only on singular posts/pages that contain a code block; 
Prism core and grammars are loaded with the <code>defer</code> strategy so they 
never block rendering.</li>
<li>Dark-mode aware out of the box — with the bundled Default — Auto 
theme (selected on first install), code blocks follow each visitor’s 
 prefers-color-scheme automatically. Override from 
Tools → Code Blocks by switching to Default — Always light / 
Always dark, or by picking any of the static Prism themes.</li>
</ul>
<h4>How it works</h4>
The chosen language is stored as a <code>language</code> block attribute on 
 core/code, which lives in the block delimiter comment rather than the 
saved markup. That means blocks without a language stay valid and 
existing content is never migrated.
On render, the plugin uses <code>WP_HTML_Tag_Processor</code> to add <code>data-language</code> 
to the <code><pre></code> and <code>language-xxx</code> to the <code><code></code> server-side — so KSES 
won’t strip <code>data-*</code> attributes for non-admin authors, and there is no 
block-validation churn.
Prism core and the per-language grammars are bundled under 
 assets/prism/ at v1.30.0 (MIT — see <code>assets/prism/LICENSE.txt</code>). They 
register as deferred scripts with explicit dependency ordering (e.g. 
 markup-templating before <code>php</code>, <code>clike</code> before languages that extend 
it). The copy-button script depends on the last grammar in the chain, 
so all of Prism is present before the copy UI is wired up. Reading 
 code.textContent returns the original source even after Prism wraps 
tokens in spans, so the copied text is unaffected by highlighting.
Self-hosting Prism (rather than loading from a public CDN) keeps the 
third-party-script supply chain off the plugin’s surface and means the 
plugin works on sites with strict CSPs or no external egress.
<h3>Privacy</h3>
Privacy-first: this plugin includes no analytics, no tracking, and no data gathering. Nothing about you, your site, or your visitors is ever collected or sent anywhere.

Coywolf Code Block Enhancer

Syntax highlighting and a copy-to-clipboard button for the native WordPress Code block, plus a language picker in the editor sidebar.

Coywolf Code Block Enhancer vs Copy Anything to Clipboard for WordPress – Copy Button, Copy Text & Copy Code