update docs

docs/getting-started.md

@@ -209,7 +209,7 @@ Next, `cd` into your new project folder.
 
 Framework’s local development server lets you preview your site in the browser as you make rapid changes. The preview server generates pages on-the-fly: as you edit files in your editor, changes are instantly streamed to your browser.
 
-<div class="tip">You can work offline with the preview server, but you must be connected to the internet to <a href="./javascript/imports">import libraries</a> from npm. In the future, we intend to support self-hosting imported libraries; please upvote <a href="https://github.com/observablehq/framework/issues/20">#20</a> and <a href="https://github.com/observablehq/framework/issues/360">#360</a> if you are interested in this feature.</div>
+<div class="tip">You can develop offline, but you must connect to the internet to <a href="./javascript/imports">import new libraries</a> from npm. Framework self-hosts imports: modules are downloaded from npm and stored in a local cache the first time you import them, and are included in <code>dist</code> when you build your project. In the future, we also plan to support importing from <code>node_modules</code>; please upvote <a href="https://github.com/observablehq/framework/issues/360">#360</a> if you are interested in this feature.</div>
 
 To start the preview server using npm:
 

docs/javascript/imports.md

@@ -108,7 +108,7 @@ In addition to resolving versions of directly-imported modules, Observable Frame
 <link rel="modulepreload" href="https://cdn.jsdelivr.net/npm/[email protected]/+esm">
 ```
 
-<div class="note">We’d also like to download imported modules from the CDN during build, making the built site entirely self-contained; see <a href="https://github.com/observablehq/framework/issues/20">#20</a>. This would further enable subresource integrity hashes; see <a href="https://github.com/observablehq/framework/issues/306">#306</a>.</div>
+<div class="note">Framework automatically downloads <code>npm:</code> imports from npm during preview and build, making the built site entirely self-contained. If you prefer not to self-host a module, and instead load it from an external server at runtime, import a full URL instead of using the <code>npm:</code> protocol.</div>
 
 ## Implicit imports
 

docs/routing.md

@@ -157,14 +157,14 @@ The resulting output root is:
 .
 ├─ dist
 │  ├─ _import
-│  │  └─ chart.js
+│  │  └─ chart.c79c2048.js
 │  ├─ _observablehq
 │  │  └─ ... # additional assets for serving the site
 │  └─ index.html
 └─ ...
 ```
 
-The import declaration is automatically rewritten during build to point to `./_import/chart.js` instead of `./chart.js`. (In the future [#260](https://github.com/observablehq/framework/issues/260), Observable Framework will add a content hash to the imported module name for cache-breaking.)
+The import declaration is automatically rewritten during build to point to `./_import/chart.c79c2048.js` instead of `./chart.js`. The content hash `c79c2048` ensures cache-breaking during deploy, and allows assets to be marked as `cache-control: immutable` to improve performance.
 
 Use a leading slash to denote paths relative to the source root, such as `/chart.js` instead of `./chart.js`. This allows you to use the same path to import a module from anywhere, even in nested folders. Observable Framework always generates relative links so that the generated site can be served under a base path.
 
@@ -186,18 +186,18 @@ Any files referenced by `FileAttachment` will automatically be copied to the `_f
 .
 ├─ dist
 │  ├─ _file
-│  │  └─ quakes.csv
+│  │  └─ quakes.e5f2eb94.csv
 │  ├─ _observablehq
 │  │  └─ ... # additional assets for serving the site
 │  └─ index.html
 └─ ...
 ```
 
-`FileAttachment` references are automatically rewritten during build; for example, a reference to `quakes.csv` might be replaced with `_file/quakes.csv`. (In the future [#260](https://github.com/observablehq/framework/issues/260), Observable Framework will add a content hash to the attached file name for cache-breaking.) Only the files you reference statically are copied to the output root (`dist`), so nothing extra or unused is included in the built site.
+`FileAttachment` references are automatically rewritten during build; for example, a reference to `quakes.csv` might be replaced with `_file/quakes.e5f2eb94.csv`. (As with imports, file names are given a content hash, here `e5f2eb94`, to improve performance.) Only the files you reference statically are copied to the output root (`dist`), so nothing extra or unused is included in the built site.
 
 [Imported modules](#imports) can use `FileAttachment`, too. In this case, the path to the file is _relative to the importing module_ in the same fashion as `import`; this is accomplished by resolving relative paths at runtime with [`import.meta.url`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/import.meta).
 
-Some additional assets are automatically promoted to file attachments and copied to `_file`. For example, if you have a `<link rel="stylesheet" href="style.css">` declared statically in a Markdown page, the `style.css` file will be copied to `_file`, too. The HTML elements eligible for file attachments are `audio`, `img`, `link`, `picture`, and `video`.
+Some additional assets are automatically promoted to file attachments and copied to `_file`. For example, if you have a `<link rel="stylesheet" href="style.css">` declared statically in a Markdown page, the `style.css` file will be copied to `_file`, too (and the file name given a content hash). The HTML elements eligible for file attachments are `audio`, `img`, `link`, `picture`, and `video`.
 
 ## Data loaders
 
@@ -223,7 +223,7 @@ This will produce the following output root:
 .
 ├─ dist
 │  ├─ _file
-│  │  └─ quakes.json
+│  │  └─ quakes.99da78d9.json
 │  ├─ _observablehq
 │  │  └─ ... # additional assets for serving the site
 │  └─ index.html
@@ -257,7 +257,7 @@ Becomes this output:
 ├─ dist
 │  ├─ _file
 │  │  └─ quakes
-│  │     └─ 2021.csv
+│  │     └─ 2021.e5f2eb94.csv
 │  ├─ _observablehq
 │  │  └─ ... # additional assets for serving the site
 │  └─ index.html