Add explanation for search_index file

svelte/src/filesystem/viewers/Audio.svelte

@@ -41,7 +41,7 @@ onMount(() => {
 
 <FileTitle title={state.base.name}/>
 
-<TextBlock>
+<TextBlock width="1000px">
 	<audio
 		bind:this={player}
 		class="player"

svelte/src/filesystem/viewers/File.svelte

@@ -2,6 +2,7 @@
 import { createEventDispatcher } from "svelte";
 import IconBlock from "../../file_viewer/viewers/IconBlock.svelte";
 import { fs_thumbnail_url } from "../FilesystemUtil";
+import TextBlock from "../../file_viewer/viewers/TextBlock.svelte";
 let dispatch = createEventDispatcher()
 
 export let state
@@ -21,6 +22,50 @@ export let state
 	</button>
 </IconBlock>
 
+{#if state.base.path === "/me/.search_index.gz"}
+	<TextBlock>
+		<p>
+			Congratulations! You have found the search index. One of the
+			filesystem's dirty little secrets.
+		</p>
+		<p>
+			I needed a place to store an index of each user's files so I could
+			make them searchable. Now, there are search databases like
+			ElasticSearch and such, but that's a lot of work to set up and
+			maintain.. Instead I opted to simply put the full path of every file
+			in your filesystem in a text file. That's what you're looking at
+			here. That can add up to a lot of data, but since the paths usually
+			have a lot of repetitive elements it compresses incredibly well.
+			You'd be hard-pressed to grow this index over even 1 MB. Honestly,
+			this search system is incredibly efficient, I'd be surprised if
+			EleasticSearch could even match it.
+		</p>
+		<p>
+			This file is updated 10 minutes after the last time you modify a
+			file on your filesystem. So if you're constantly uploading and
+			deleting files your search index might never update and you will be
+			left with stale search results.
+		</p>
+		<p>
+			If you delete this file then search will stop working until the file
+			is regenerated 10 minutes later. If you replace this file with a
+			different file then that file will be overwritten 10 minutes later.
+			And if you replace this file with a directory with the same name
+			then search will stop working completely until you delete the
+			directory (yes, I tested this case).
+		</p>
+		<p>
+			Each time you type a search term in the search dialog this file gets
+			decompressed and searched on the fly. There is no trickery here, the
+			file simply gets read line by line. Modern CPUs are incredibly good
+			at searching for text. I benchmarked it once, I don't remember the
+			exact numbers but it was somewhere along the lines of one gigabyte
+			of text per second. Fast enough to be unnoticeable even if you have
+			millions of files in your filesystem.
+		</p>
+	</TextBlock>
+{/if}
+
 <style>
 h1 {
 	text-shadow: 1px 1px 3px var(--shadow_color);