diff --git a/ext/wasm/sqlite3-opfs-async-proxy.js b/ext/wasm/sqlite3-opfs-async-proxy.js
index 88fdfa603a..1ff9397027 100644
--- a/ext/wasm/sqlite3-opfs-async-proxy.js
+++ b/ext/wasm/sqlite3-opfs-async-proxy.js
@@ -10,10 +10,10 @@
 
   ***********************************************************************
 
-  A EXTREMELY INCOMPLETE and UNDER CONSTRUCTION experiment for OPFS: a
-  Worker which manages asynchronous OPFS handles on behalf of a
-  synchronous API which controls it via a combination of Worker
-  messages, SharedArrayBuffer, and Atomics.
+  An INCOMPLETE and UNDER CONSTRUCTION experiment for OPFS: a Worker
+  which manages asynchronous OPFS handles on behalf of a synchronous
+  API which controls it via a combination of Worker messages,
+  SharedArrayBuffer, and Atomics.
 
   Highly indebted to:
 
@@ -109,8 +109,8 @@ const getDirForPath = async function f(absFilename, createDirs = false){
 */
 const storeAndNotify = (opName, value)=>{
   log(opName+"() is notify()ing w/ value:",value);
-  Atomics.store(state.opBuf, state.opIds[opName], value);
-  Atomics.notify(state.opBuf, state.opIds[opName]);
+  Atomics.store(state.opSABView, state.opIds[opName], value);
+  Atomics.notify(state.opSABView, state.opIds[opName]);
 };
 
 const isInt32 = function(n){
@@ -294,8 +294,8 @@ navigator.storage.getDirectory().then(function(d){
           state.verbose = opt.verbose ?? 2;
           state.fileBufferSize = opt.fileBufferSize;
           state.fbInt64Offset = opt.fbInt64Offset;
-          state.opSab = opt.opSab;
-          state.opBuf = new Int32Array(state.opSab);
+          state.opSAB = opt.opSAB;
+          state.opSABView = new Int32Array(state.opSAB);
           state.opIds = opt.opIds;
           state.sq3Codes = opt.sq3Codes;
           Object.keys(vfsAsyncImpls).forEach((k)=>{
diff --git a/ext/wasm/x-sync-async.js b/ext/wasm/x-sync-async.js
index c3027585b1..9329e765ac 100644
--- a/ext/wasm/x-sync-async.js
+++ b/ext/wasm/x-sync-async.js
@@ -10,10 +10,20 @@
 
   ***********************************************************************
 
-  A EXTREMELY INCOMPLETE and UNDER CONSTRUCTION experiment for OPFS.
+  An INCOMPLETE and UNDER CONSTRUCTION experiment for OPFS.
   This file holds the synchronous half of an sqlite3_vfs
   implementation which proxies, in a synchronous fashion, the
-  asynchronous OPFS APIs using a second Worker.
+  asynchronous OPFS APIs using a second Worker, implemented
+  in sqlite3-opfs-async-proxy.js.
+
+  Summary of how this works:
+
+  This file uses the sqlite3.StructBinder-created struct wrappers for
+  sqlite3_vfs, sqlite3_io_methods, ans sqlite3_file to set up a
+  conventional sqlite3_vfs (except that it's implemented in JS). The
+  methods which require OPFS APIs use a separate worker (hereafter called the
+  OPFS worker) to access that functionality. This worker and that one
+  use SharedBufferArray
 */
 'use strict';
 /**
@@ -36,6 +46,16 @@ const initOpfsVfs = function(sqlite3){
   };
   warn("This file is very much experimental and under construction.",self.location.pathname);
 
+  if(self.window===self ||
+     !self.SharedBufferArray ||
+     !self.FileSystemHandle ||
+     !self.FileSystemDirectoryHandle ||
+     !self.FileSystemFileHandle ||
+     !self.FileSystemFileHandle.prototype.createSyncAccessHandle ||
+     !navigator.storage.getDirectory){
+    warn("This environment does not have OPFS support.");
+  }
+
   const capi = sqlite3.capi;
   const wasm = capi.wasm;
   const sqlite3_vfs = capi.sqlite3_vfs
@@ -44,7 +64,6 @@ const initOpfsVfs = function(sqlite3){
         || toss("Missing sqlite3.capi.sqlite3_file object.");
   const sqlite3_io_methods = capi.sqlite3_io_methods
         || toss("Missing sqlite3.capi.sqlite3_io_methods object.");
-  const StructBinder = sqlite3.StructBinder || toss("Missing sqlite3.StructBinder.");
 
   const W = new Worker("sqlite3-opfs-async-proxy.js");
   const wMsg = (type,payload)=>W.postMessage({type,payload});
@@ -72,7 +91,7 @@ const initOpfsVfs = function(sqlite3){
     state.opIds.xSync = i++;
     state.opIds.xTruncate = i++;
     state.opIds.xWrite = i++;
-    state.opSab = new SharedArrayBuffer(i * 4);
+    state.opSAB = new SharedArrayBuffer(i * 4/*sizeof int32*/);
   }
 
   state.sq3Codes = Object.create(null);
@@ -91,13 +110,13 @@ const initOpfsVfs = function(sqlite3){
 
   const isWorkerErrCode = (n)=>!!state.sq3Codes._reverse[n];
   
-  const opStore = (op,val=-1)=>Atomics.store(state.opBuf, state.opIds[op], val);
-  const opWait = (op,val=-1)=>Atomics.wait(state.opBuf, state.opIds[op], val);
+  const opStore = (op,val=-1)=>Atomics.store(state.opSABView, state.opIds[op], val);
+  const opWait = (op,val=-1)=>Atomics.wait(state.opSABView, state.opIds[op], val);
 
   /**
      Runs the given operation in the async worker counterpart, waits
      for its response, and returns the result which the async worker
-     writes to the given op's index in state.opBuf. The 2nd argument
+     writes to the given op's index in state.opSABView. The 2nd argument
      must be a single object or primitive value, depending on the
      given operation's signature in the async API counterpart.
   */
@@ -105,7 +124,7 @@ const initOpfsVfs = function(sqlite3){
     opStore(op);
     wMsg(op, args);
     opWait(op);
-    return Atomics.load(state.opBuf, state.opIds[op]);
+    return Atomics.load(state.opSABView, state.opIds[op]);
   };
 
   const wait = (ms,value)=>{
@@ -151,16 +170,17 @@ const initOpfsVfs = function(sqlite3){
   opfsVfs.$szOsFile = capi.sqlite3_file.structInfo.sizeof;
   opfsVfs.$mxPathname = 1024/*sure, why not?*/;
   opfsVfs.$zName = wasm.allocCString("opfs");
+  // All C-side memory of opfsVfs is zeroed out, but just to be explicit:
+  opfsVfs.$xDlOpen = opfsVfs.$xDlError = opfsVfs.$xDlSym = opfsVfs.$xDlClose = null;
   opfsVfs.ondispose = [
     '$zName', opfsVfs.$zName,
-    'cleanup dVfs', ()=>(dVfs ? dVfs.dispose() : null)
+    'cleanup default VFS wrapper', ()=>(dVfs ? dVfs.dispose() : null),
+    'cleanup opfsIoMethods', ()=>opfsIoMethods.dispose()
   ];
   if(dVfs){
     opfsVfs.$xSleep = dVfs.$xSleep;
     opfsVfs.$xRandomness = dVfs.$xRandomness;
   }
-  // All C-side memory of opfsVfs is zeroed out, but just to be explicit:
-  opfsVfs.$xDlOpen = opfsVfs.$xDlError = opfsVfs.$xDlSym = opfsVfs.$xDlClose = null;
   /**
      Pedantic sidebar about opfsVfs.ondispose: the entries in that array
      are items to clean up when opfsVfs.dispose() is called, but in this
@@ -383,7 +403,7 @@ const initOpfsVfs = function(sqlite3){
       const dbFile = "/sanity/check/file";
       let rc = vfsSyncWrappers.xOpen(opfsVfs.pointer, dbFile,
                                      fid, openFlags, pOut);
-      log("open rc =",rc,"state.opBuf[xOpen] =",state.opBuf[state.opIds.xOpen]);
+      log("open rc =",rc,"state.opSABView[xOpen] =",state.opSABView[state.opIds.xOpen]);
       if(isWorkerErrCode(rc)){
         error("open failed with code",rc);
         return;
@@ -399,7 +419,7 @@ const initOpfsVfs = function(sqlite3){
       log("xSleep()ing before close()ing...");
       opRun('xSleep',1500);
       rc = ioSyncWrappers.xClose(fid);
-      log("xClose rc =",rc,"opBuf =",state.opBuf);
+      log("xClose rc =",rc,"opSABView =",state.opSABView);
       log("Deleting file:",dbFile);
       opRun('xDelete', dbFile);
     }finally{
@@ -416,13 +436,31 @@ const initOpfsVfs = function(sqlite3){
           /*Pass our config and shared state on to the async worker.*/
           wMsg('init',state);
           break;
-        case 'inited':
+        case 'inited':{
           /*Indicates that the async partner has received the 'init',
             so we now know that the state object is no longer subject to
             being copied by a pending postMessage() call.*/
-          state.opBuf = new Int32Array(state.opSab);
-          sanityCheck();
+          try {
+            const rc = capi.sqlite3_vfs_register(opfsVfs.pointer, opfsVfs.$zName);
+            if(rc){
+              opfsVfs.dispose();
+              toss("sqlite3_vfs_register(OPFS) failed with rc",rc);
+            }
+            if(opfsVfs.pointer !== capi.sqlite3_vfs_find("opfs")){
+              toss("BUG: sqlite3_vfs_find() failed for just-installed OPFS VFS");
+            }
+            capi.sqlite3_vfs_register.addReference(opfsVfs, opfsIoMethods);
+            state.opSABView = new Int32Array(state.opSAB);
+            if(self.location && +self.location.port > 1024){
+              log("Running sanity check for dev mode...");
+              sanityCheck();
+            }
+            warn("End of (very incomplete) OPFS setup.", opfsVfs);
+          }catch(e){
+            error(e);
+          }
           break;
+        }
         default:
           error("Unexpected message from the async worker:",data);
           break;
diff --git a/manifest b/manifest
index cce6558812..bef8fab86f 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sthe\sremaining\svfs/io_methods\swrappers\sto\sthe\sOPFS\ssync/async\sproxy,\sbut\smost\sare\snot\syet\stested.
-D 2022-09-17T20:50:12.684
+C Generic\scleanups\sin\sthe\sOPFS\ssync/async\sproxy.
+D 2022-09-17T21:13:26.228
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -523,7 +523,7 @@ F ext/wasm/speedtest1.html fbb8e4d1639028443f3687a683be660beca6927920545cf6b1fdf
 F ext/wasm/split-speedtest1-script.sh a3e271938d4d14ee49105eb05567c6a69ba4c1f1293583ad5af0cd3a3779e205 x
 F ext/wasm/sql/000-mandelbrot.sql 775337a4b80938ac8146aedf88808282f04d02d983d82675bd63d9c2d97a15f0
 F ext/wasm/sql/001-sudoku.sql 35b7cb7239ba5d5f193bc05ec379bcf66891bce6f2a5b3879f2f78d0917299b5
-F ext/wasm/sqlite3-opfs-async-proxy.js 62024877ad13fdff1834581ca1951ab58bda431e4d548aaaf4506ea54f0ed2de
+F ext/wasm/sqlite3-opfs-async-proxy.js ceb5e3a190bfd42d25fc137b3aaf09adf6469b5f1e33528a64ce7ff74e5ef5b1
 F ext/wasm/sqlite3-worker1-promiser.js 92b8da5f38439ffec459a8215775d30fa498bc0f1ab929ff341fc3dd479660b9
 F ext/wasm/sqlite3-worker1.js 0c1e7626304543969c3846573e080c082bf43bcaa47e87d416458af84f340a9e
 F ext/wasm/testing-worker1-promiser.html 6eaec6e04a56cf24cf4fa8ef49d78ce8905dde1354235c9125dca6885f7ce893
@@ -534,7 +534,7 @@ F ext/wasm/testing2.html a66951c38137ff1d687df79466351f3c734fa9c6d9cce71d3cf97c2
 F ext/wasm/testing2.js 25584bcc30f19673ce13a6f301f89f8820a59dfe044e0c4f2913941f4097fe3c
 F ext/wasm/wasmfs.make 21a5cf297954a689e0dc2a95299ae158f681cae5e90c10b99d986097815fd42d
 F ext/wasm/x-sync-async.html 717b0d3bee96e49cbd36731bead497ab27a8bf3a3b23dd11e40e61d4ac9e8b80
-F ext/wasm/x-sync-async.js 05c0b49adae0600c5ad12f3325e0873ab1f07b99c2bb017f32b50a4f701490f1
+F ext/wasm/x-sync-async.js c99a6f98a8b0ccb43b2883a1bc1da42d0d84b26b5d4fd99d2f053ffe209a0a1f
 F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895 x
 F ltmain.sh 3ff0879076df340d2e23ae905484d8c15d5fdea8
 F magic.txt 8273bf49ba3b0c8559cb2774495390c31fd61c60
@@ -2030,8 +2030,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 38da059b472415da52f57de7332fbeb8a91e3add1f4be3ff9c1924b52672f77c
-R 8887512b2075b067b4aa7969d08f1316
+P 44db9132145b3072488ea91db53f6c06be74544beccad5fd07efd22c0f03dc04
+R 75c9aa6717389505aa78f157abdf6d44
 U stephan
-Z 1bf4c438e48bd1dc1717362060b2f357
+Z 6a0a0bcb470dbb44e9d0c87c09f1fedd
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 7d2261af8e..4f626ec440 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-44db9132145b3072488ea91db53f6c06be74544beccad5fd07efd22c0f03dc04
\ No newline at end of file
+f36bddbe54c3acbfaa958042e4d24724f130bdca551401033f9bc63f3da73492
\ No newline at end of file