```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns3:query_definition xmlns:ns2="http://www.i2b2.org/xsd/cell/crc/psm/1.1/" xmlns:ns4="http://www.i2b2.org/xsd/cell/crc/psm/analysisdefinition/1.1/" xmlns:ns3="http://www.i2b2.org/xsd/cell/crc/psm/querydefinition/1.1/">
    <query_name>Principal Diagn@02:06:14</query_name>
    <query_timing>ANY</query_timing>
    <specificity_scale>0</specificity_scale>
    <panel>
        <panel_number>1</panel_number>
        <panel_timing>ANY</panel_timing>
        <panel_accuracy_scale>100</panel_accuracy_scale>
        <invert>0</invert>
        <total_item_occurrences>1</total_item_occurrences>
        <item>
            <hlevel>2</hlevel>
            <item_name>Diseases of appendix (k35-k38)</item_name>
            <item_key>\\ICD10_ICD9\Diagnoses\(K00-K94) Dise~rl1r\(K35-K38) Dise~lkd6\</item_key>
            <item_icon>FA</item_icon>
            <tooltip>Diagnoses \ Diseases of the digestive system (k00-k94) \ Diseases of appendix (k35-k38)</tooltip>
            <class>ENC</class>
            <constrain_by_modifier>
                <modifier_name>Principal Diagnosis</modifier_name>
                <modifier_key>\\ICD10_ICD9\Principal Diagnosis\</modifier_key>
                <applied_path>\Diagnoses\(K00-K94) Dise~rl1r\%</applied_path>
            </constrain_by_modifier>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
</ns3:query_definition>

```

I want to find all records where the principal diagnosis is related to diseases of the appendix (ICD10 codes K35-K38) within the category of diseases of the digestive system (ICD10 codes K0-K94). The specificity scale is set to 0, meaning any occurrence of the specified diagnosis will be included, and the accuracy scale is set to 100, indicating the highest level of confidence. This query is part of a panel with a single item, and the class is set to ENC (Encounter).