diff -r 8e4731a2a041 -r 8585399f26f6 src/Pure/General/utf8.scala
--- a/src/Pure/General/utf8.scala	Fri Jul 05 10:55:02 2024 +0200
+++ b/src/Pure/General/utf8.scala	Fri Jul 05 11:38:21 2024 +0200
@@ -11,53 +11,7 @@
 
 
 object UTF8 {
-  /* charset */
-
   val charset: Charset = StandardCharsets.UTF_8
 
   def bytes(s: String): Array[Byte] = s.getBytes(charset)
-
-
-  /* permissive UTF-8 decoding */
-
-  // see also https://en.wikipedia.org/wiki/UTF-8#Description
-  // overlong encodings enable byte-stuffing of low-ASCII
-
-  def decode_permissive(bytes: Bytes): String = {
-    val size = bytes.size
-    val buf = new java.lang.StringBuilder((size min Space.GiB(1).bytes).toInt)
-    var code = -1
-    var rest = 0
-    def flush(): Unit = {
-      if (code != -1) {
-        if (rest == 0 && Character.isValidCodePoint(code)) buf.appendCodePoint(code)
-        else buf.append('\uFFFD')
-        code = -1
-        rest = 0
-      }
-    }
-    def init(x: Int, n: Int): Unit = {
-      flush()
-      code = x
-      rest = n
-    }
-    def push(x: Int): Unit = {
-      if (rest <= 0) init(x, -1)
-      else {
-        code <<= 6
-        code += x
-        rest -= 1
-      }
-    }
-    for (i <- 0L until size) {
-      val c = bytes.char(i)
-      if (c < 128) { flush(); buf.append(c) }
-      else if ((c & 0xC0) == 0x80) push(c & 0x3F)
-      else if ((c & 0xE0) == 0xC0) init(c & 0x1F, 1)
-      else if ((c & 0xF0) == 0xE0) init(c & 0x0F, 2)
-      else if ((c & 0xF8) == 0xF0) init(c & 0x07, 3)
-    }
-    flush()
-    buf.toString
-  }
 }