Topic about sources of information available to developers and dApps (#313)

* Topic about sources of information available to developers and dApps

* Can get current balance

Author: timothymcmackin

Diff for: docs/developing/information.md

@@ -0,0 +1,48 @@
+---
+title: Getting information about the blockchain
+authors: Tim McMackin
+last_update:
+  date: 8 February 2024
+---
+
+Developers and dApps can get information about the Tezos blockchain, such as account balances, from these sources:
+
+## The Octez client
+
+The [The Octez client](./octez-client) provides information about accounts, addresses, and many other things.
+For example, you can get the balance of an account with this command:
+
+```bash
+octez-client get balance for tz1QCVQinE8iVj1H2fckqx6oiM85CNJSK9Sx
+```
+
+## The RPC protocol
+
+The [RPC](../architecture/rpc) protocol provides information about the blockchain that nodes use to communicate with each other.
+This data is not always in the format that developers and dApps need.
+For example, the RPC interface does not provide a way to get information about a specific operation by its hash.
+
+You can get some information about accounts, contracts, and other things from RPC requests.
+For example, this RPC request gets the current balance of an account:
+
+```bash
+curl -X GET https://rpc.ghostnet.teztnets.com/chains/main/blocks/head/context/contracts/tz1QCVQinE8iVj1H2fckqx6oiM85CNJSK9Sx/balance
+```
+
+## Indexers
+
+Indexers are off-chain applications that retrieve blockchain data, process it, and store it in a way that makes it easier to search and use.
+For example, you can use the [TZKT API](https://api.tzkt.io/) to get the recent operations an account made with this request:
+
+```bash
+curl -X GET https://api.ghostnet.tzkt.io/v1/accounts/tz1QCVQinE8iVj1H2fckqx6oiM85CNJSK9Sx/operations
+```
+
+For more information, see [Indexers](./information/indexers).
+
+## Block explorers
+
+Block explorers use data from indexers to show information in a human-friendly interface.
+For example, this link shows information about a contract, including its current storage, entrypoints, and transaction history: https://better-call.dev/ghostnet/KT1R4i4qEaxF7v3zg1M8nTeyrqk8JFmdGLuu/operations
+
+For more information about block explorers, see [Block explorers](./information/block-explorers).

Diff for: sidebars.js

@@ -88,10 +88,10 @@ const sidebars = {
         {
           type: 'category',
           label: 'Getting information about the blockchain',
-          // link: { // TODO
-          //   id: 'developing/information',
-          //   type: 'doc',
-          // },
+          link: {
+            id: 'developing/information',
+            type: 'doc',
+          },
           items: [
             {
               type: 'category',