What is the key and value doing in the Couchbase C SDK's Hello World example

In this link: Install and Start Using the C SDK with Couchbase Server | Couchbase Docs

I see this code example to use Couchbase SDK below , but what are the key and value pointers representing? Is the key supposed to be the document name?

static void store_callback(lcb_INSTANCE *instance, int cbtype, const lcb_RESPSTORE *resp)
const char *key;
size_t nkey;
uint64_t cas;
lcb_respstore_key(resp, &key, &nkey);
lcb_respstore_cas(resp, &cas);
printf(“status: %s, key: %.*s, CAS: 0x%” PRIx64 “\n”,
lcb_strerror_short(lcb_respstore_status(resp)), (int)nkey, key, cas);

lcb_install_callback3(instance, LCB_CALLBACK_STORE, (lcb_RESPCALLBACK)store_callback);

lcb_STATUS rc;
lcb_CMDSTORE *cmd;
const char *collection = NULL, *scope = NULL;
size_t collection_len = 0, scope_len = 0;
const char *key = “my-document”;
const char *value = “{“name”: “mike”}”;
rc = lcb_cmdstore_create(&cmd, LCB_STORE_UPSERT);
rc = lcb_cmdstore_collection(cmd, scope, scope_len, collection, collection_len);
rc = lcb_cmdstore_key(cmd, key, strlen(key));
rc = lcb_cmdstore_value(cmd, value, strlen(value));
rc = lcb_store(instance, NULL, cmd);
rc = lcb_cmdstore_destroy(cmd);
rc = lcb_wait(instance);