diff --git a/toys/README b/toys/README
new file mode 100644
index 0000000..df08137
--- /dev/null
+++ b/toys/README
@@ -0,0 +1,3 @@
+checkextensions
+===============
+Reports files whose extension does not match the (detected) mime-type.
diff --git a/toys/checkextensions b/toys/checkextensions
new file mode 100755
index 0000000..5ee9167
--- /dev/null
+++ b/toys/checkextensions
@@ -0,0 +1,103 @@
+#!/bin/bash
+
+# config structures
+declare -A			\
+	destinationchannels	\
+	destinationfat32compat	\
+	destinationcopymime	\
+	destinationformat	\
+	destinationfrequency	\
+	destinationid		\
+	destinationloss		\
+	destinationmaxbps	\
+	destinationnormalize	\
+	destinationpath		\
+	destinationquality	\
+	destinationrename	\
+	destinationnoresample	\
+	destinationrenamepath	\
+	destinationskipmime	\
+|| {
+	echo "Check your Bash version. You need >= 4.0" >&2
+	exit $EBASHVERS
+}
+
+declare -r				\
+	DOCDIR=./doc			\
+	LIBDIR=./lib			\
+	SHAREDIR=./share
+declare -r				\
+	exampleconf=$DOCDIR/example.cfg	\
+	schema=$SHAREDIR/schema.sql	\
+					\
+	oldIFS="$IFS"
+
+LC_ALL=C
+
+shopt -s extglob
+
+for function in "$LIBDIR"/*/*
+do
+	source "$function"
+done
+
+getConfig
+
+openDatabase
+
+getFiles
+
+echo '
+	SELECT
+		source_files.id,
+		source_files.filename,
+		mime_types.mime_text
+	FROM
+			source_files
+	INNER JOIN	mime_types
+		ON	source_files.mime_type = mime_types.id
+	;
+	SELECT	"AtOM:NoMoreFiles";
+' >&3
+
+while read -u4 line
+do
+	if [[ $line == AtOM:NoMoreFiles ]]
+	then
+		break
+	fi
+	fileid=${line%%|*}
+	rest="${line#*|}|"
+	filename=${rest%%|*}
+	rest=${rest#*|}
+	mimetype=${rest%%|*}
+	rest=${rest#*|}
+	case "$mimetype" in
+		'audio/mpeg')
+			if [[ ${filename##*.} != mp3 ]]
+			then
+				echo "$filename: MP3 (.mp3)"
+			fi
+		;;
+		'application/ogg vorbis')
+			if [[ ${filename##*.} != ogg ]]
+			then
+				echo "$filename: Ogg Vorbis (.ogg)"
+			fi
+		;;
+		'application/ogg opus')
+			if [[ ${filename##*.} != opus ]]
+			then
+				echo "$filename: Opus (.opus)"
+			fi
+		;;
+		'audio/x-flac')
+			if [[ ${filename##*.} != flac ]]
+			then
+				echo "$filename: FLAC (.flac)"
+			fi
+		;;
+	esac
+done
+
+closeDatabase