Various potential schema for badge indexing.

badgeindex-schema.json

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "title": "Badge List",
    "description": "An index of available Open Badge lists",
    "type": "object",
    "required": ["badgeindex"],
    "additionalProperties": false,
    "properties": {
        "badgeindex": {
            "description": "Container for a set of badge lists.",
            "type": "array",
            "minItems": 1,
            "uniqueItems": true,
            "items": {
                "title": "Badge List",
                "description": "Container for the data needed to describe a badge list.",
                "type": "object",
                "required": ["location"],
                "additionalProperties": false,
                "properties": {
                    "location": {
                        "description": "The location URI of a badge list.",
                        "type": "string",
                        "format": "uri"
                    }
                }
            }
        }
    }
}

badgeindex-schema.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://openbadges.org/schemas/1.0"
            xmlns="http://openbadges.org/schemas/1.0"
            elementFormDefault="qualified">

    <xsd:annotation>
        <xsd:documentation>
            XML Schema for Badge List files.
            Last Modifed 2013-08-01
        </xsd:documentation>
    </xsd:annotation>

    <xsd:element name="badgeindex">
        <xsd:annotation>
            <xsd:documentation>
                Container for a set of badge lists.
                This is the root element of the XML file.
            </xsd:documentation>
        </xsd:annotation>
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="badges" type="tBadges" maxOccurs="unbounded"/>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <xsd:complexType name="tBadges">
        <xsd:annotation>
            <xsd:documentation>
                Container for the data needed to describe a badge list.
            </xsd:documentation>
        </xsd:annotation>
        <xsd:sequence>
            <xsd:element name="location" type="tLocation"/>
        </xsd:sequence>
    </xsd:complexType>

    <xsd:simpleType name="tLocation">
        <xsd:annotation>
            <xsd:documentation>
                REQUIRED: The location URI of a badge list.
                The URI must conform to RFC 2396 (http://www.ietf.org/rfc/rfc2396.txt).
            </xsd:documentation>
        </xsd:annotation>
        <xsd:restriction base="xsd:anyURI">
            <xsd:minLength value="12"/>
            <xsd:maxLength value="2048"/>
        </xsd:restriction>
    </xsd:simpleType>

</xsd:schema>

badgelist-schema.json

{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "title": "Badge List",
    "description": "A list of available Open Badges",
    "type": "object",
    "required": ["badgelist"],
    "additionalProperties": false,
    "properties": {
        "badgelist": {
            "description": "Container for a set of badge elements.",
            "type": "array",
            "items": {
                "title": "Badge",
                "description": "Container for the data needed to describe a badge assertion to extract.",
                "type": "object",
                "required": ["location"],
                "additionalProperties": false,
                "properties": {
                    "location": {
                        "description": "The location URI of a badge assertion.",
                        "type": "string",
                        "format": "uri"
                    },
                    "priority": {
                        "description": "The priority of a particular badge relative to other badges on the same site.",
                        "type": "number",
                        "minimum": 0.0,
                        "maximum": 1.0
                    }
                }
            }
        }
    }
}

badgelist-schema.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://openbadges.org/schemas/0.1"
            xmlns="http://schemas.openbadges.org/schemas/0.1"
            elementFormDefault="qualified">

    <xsd:annotation>
        <xsd:documentation>
            XML Schema for Badge List files.
            Last Modifed 2013-08-01
        </xsd:documentation>
    </xsd:annotation>

    <xsd:element name="badgelist">
        <xsd:annotation>
            <xsd:documentation>
                Container for a set of badge elements.
                This is the root element of the XML file.
            </xsd:documentation>
        </xsd:annotation>
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="badge" type="tBadge" maxOccurs="unbounded"/>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <xsd:complexType name="tBadge">
        <xsd:annotation>
            <xsd:documentation>
                Container for the data needed to describe a badge assertion to extract.
            </xsd:documentation>
        </xsd:annotation>
        <xsd:sequence>
            <xsd:element name="location" type="tLocation"/>
            <xsd:element name="priority" type="tPriority" minOccurs="0"/>
        </xsd:sequence>
    </xsd:complexType>

    <xsd:simpleType name="tLocation">
        <xsd:annotation>
            <xsd:documentation>
                REQUIRED: The location URI of a badge assertion.
                The URI must conform to RFC 2396 (http://www.ietf.org/rfc/rfc2396.txt).
            </xsd:documentation>
        </xsd:annotation>
        <xsd:restriction base="xsd:anyURI">
            <xsd:minLength value="12"/>
            <xsd:maxLength value="2048"/>
        </xsd:restriction>
    </xsd:simpleType>

    <xsd:simpleType name="tPriority">
        <xsd:annotation>
            <xsd:documentation>
                OPTIONAL: The priority of a particular badge relative to other badges
                on the same site. The value for this element is a number between
                0.0 and 1.0 where 0.0 identifies the lowest priority badge(s).
                The default priority of a badge is 0.5. Priority is used to select
                between badges on your site. Setting a priority of 1.0 for all badges
                will not help you, as the relative priority of badges on your site
                is what will be considered.
            </xsd:documentation>
        </xsd:annotation>
        <xsd:restriction base="xsd:decimal">
            <xsd:minInclusive value="0.0"/>
            <xsd:maxInclusive value="1.0"/>
        </xsd:restriction>
    </xsd:simpleType>

</xsd:schema>