Add missing OP_CAT warning and update FAQ

Author: vostrnad

src/lib/utils/bitcoin/script/interpreter.ts

@@ -439,6 +439,10 @@ export const evalScript = (
       return setError(SCRIPT_ERR_DISABLED_OPCODE) // Disabled opcodes (CVE-2010-5137).
     }
 
+    if (opcode === OP_CAT) {
+      warnings.add(ScriptWarning.cat)
+    }
+
     if (opcode >= 1 && opcode <= OP_PUSHDATA4) {
       let pushBytes: number
 

src/routes/faq/+page.svelte

@@ -14,25 +14,29 @@
     Where do I find the source code?
   </dt>
   <dd>
-    In the <a
-      target="_blank"
-      rel="noreferrer"
-      href="https://github.com/vostrnad/bitcoinutils.dev">GitHub repository</a
-    >.
+    <p>
+      In the <a
+        target="_blank"
+        rel="noreferrer"
+        href="https://github.com/vostrnad/bitcoinutils.dev">GitHub repository</a
+      >.
+    </p>
   </dd>
 
   <dt>
     <PageAnchor id="debugger-initial-stack" />
     How do I add an initial stack to a script?
   </dt>
-  <dd>You can push the required stack items at the beginning of a script.</dd>
+  <dd>
+    <p>You can push the required stack items at the beginning of a script.</p>
+  </dd>
 
   <dt>
     <PageAnchor id="debugger-bitcoin-core-difference" />
     How does the script debugger differ from Bitcoin Core's script interpreter?
   </dt>
   <dd>
-    Here is a non-exhaustive list of differences:
+    <p>Here is a non-exhaustive list of differences:</p>
     <ul>
       <li>
         Because we're executing scripts without knowing the rest of the
@@ -53,6 +57,14 @@
         Both OP_CHECKMULTISIG and OP_CHECKSIGADD are implemented and can be used
         in the same script, which wouldn't normally be possible.
       </li>
+      <li>
+        OP_CAT (<a
+          target="_blank"
+          rel="noreferrer"
+          href="https://github.com/bitcoin/bips/blob/master/bip-0347.mediawiki"
+          >BIP 347</a
+        >) is implemented, even though it's currently only available on signet.
+      </li>
       <li>
         Standardness rules are not enforced, though some are implemented as
         warnings.