GET the Container id with:

Content-Type: application/ld+json;
Accept: application/ld+json; profile="http://www.w3.org/ns/anno.jsonld"

Example

GET /annotation/w3c/my-container/ HTTP/1.1
Accept: application/ld+json; profile="http://www.w3.org/ns/anno.jsonld"
Content-Type: application/ld+json;
Host: localhost:8080
Connection: close
User-Agent: Paw/3.1.5 (Macintosh; OS X/10.13.4) GCDHTTPRequest

Returns:

HTTP/1.1 200 
Link: <http://www.w3.org/ns/ldp#BasicContainer>; rel="type"
Link: <http://www.w3.org/TR/annotation-protocol/>; rel="http://www.w3.org/ns/ldp#constrainedBy"
Allow: POST,GET,OPTIONS,HEAD
Vary: Accept,Prefer
Content-Location: http://localhost:8080/annotations//w3c/my-container/
Accept-Post: application/ld+json; profile="http://www.w3.org/ns/anno.jsonld", text/turtle
Content-Type: application/ld+json; profile="http://www.w3.org/ns/anno.jsonld";charset=UTF-8
Transfer-Encoding: chunked
Date: Sun, 20 May 2018 19:52:47 GMT
Connection: close

{
  "@context" : "http://www.w3.org/ns/anno.jsonld",
  "id" : "http://localhost:8080/annotation/w3c/my-container/",
  "type" : "AnnotationCollection",
  "label" : "A Container for Web Annotations",
  "first" : {
    "type" : "AnnotationPage",
    "items" : [ {
      "id" : "http://localhost:8080/annotation/w3c/my-container/e849d4a3-b769-4925-8f08-9214804f0e92",
      "type" : "Annotation",
      "body" : {
        "type" : "TextualBody",
        "value" : "I like this page!"
      },
      "target" : "http://www.example.com/index.html"
    }, {
      "id" : "http://localhost:8080/annotation/w3c/my-container/foo-bar",
      "type" : "Annotation",
      "body" : {
        "type" : "TextualBody",
        "value" : "This one has a SLUG, so I know what id the annotation will have."
      },
      "target" : "http://www.example.com/index.html"
    } ],
    "partOf" : "http://localhost:8080/annotation/w3c/my-container/",
    "startIndex" : 0
  },
  "last" : "http://localhost:8080/annotation/w3c/my-container/?page=0&desc=1",
  "total" : 2
}

You can see the paging intrinsic to the W3C Annotation Model.

The annotation server returns:

"total" : 2

And a partOf link to the Container id:

"partOf" : "http://localhost:8080/annotation/w3c/my-container/"

And a last link to the last page in the paged sequence of Annotation Pages.

"last" : "http://localhost:8080/annotation/w3c/my-container/?page=0&desc=1"