Use urn rather that non-resolvable URL.

manifest.ttl

@@ -1,7 +1,7 @@
 @prefix lv2:  <http://lv2plug.in/ns/lv2core#> .
 @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
 
-<http://fuzzle.org/~petern/psyn/1>
+<urn:fuzzle:psyn>
   a lv2:Plugin, lv2:InstrumentPlugin;
-  lv2:binary <psyn.so>;
+  lv2:binary <libpsyn.so>;
   rdfs:seeAlso <psyn.ttl>.

psyn.c

@@ -186,7 +186,7 @@ static void run(LV2_Handle lv2instance, uint32_t sample_count)
 
 static LV2_Descriptor g_lv2descriptor =
 {
-	.URI = "http://fuzzle.org/~petern/psyn/1",
+	.URI = "urn:fuzzle:psyn",
 	.instantiate = &instantiate,
 	.connect_port = &connect_port,
 	.run = &run,

psyn.ttl

@@ -3,7 +3,7 @@
 @prefix doap: <http://usefulinc.com/ns/doap#> .
 @prefix lv2ev: <http://lv2plug.in/ns/ext/event#> .
 
-<http://fuzzle.org/~petern/psyn/1>
+<urn:fuzzle:psyn>
   a lv2:Plugin;
   doap:maintainer [
     foaf:name "Peter Nelson";