-extern struct output_format output_text_bits;
-extern struct output_format output_text_hex;
-extern struct output_format output_binary;
-extern struct output_format output_vcd;
-extern struct output_format output_ols;
-extern struct output_format output_gnuplot;
-extern struct output_format output_analog;
+/**
+ * @file
+ *
+ * Output file/data format handling.
+ */
+
+/**
+ * @defgroup grp_output Output formats
+ *
+ * Output file/data format handling.
+ *
+ * libsigrok supports several output (file) formats, e.g. binary, VCD,
+ * gnuplot, and so on. It provides an output API that frontends can use.
+ * New output formats can be added/implemented in libsigrok without having
+ * to change the frontends at all.
+ *
+ * All output modules are fed data in a stream. Devices that can stream data
+ * into libsigrok, instead of storing and then transferring the whole buffer,
+ * can thus generate output live.
+ *
+ * Output modules generate a newly allocated GString. The caller is then
+ * expected to free this with g_string_free() when finished with it.
+ *
+ * @{
+ */