ExportFieldLayoutItems.java

/*
REQUIRES https://github.com/financialforcedev/apex-mdapi

Exports all instances of field-layout items into CSV format:

Object,Field,Layout,Behavior
"account","AccountNumber","account-account %28marketing%29 layout","Edit"
"account","AccountNumber","account-account %28sales%29 layout","Edit"
......

 */

final Set<String> SOBJECT_SCOPE = new Set<String>{
    'ACCOUNT','Contact'
};

final List<String>     rows           = new List<String>();
final List<String>     columns        = new List<String>();
MetadataService.Layout layoutMetadata = null              ;
String                 objectName     = null              ;

final List<String> layouts = listLayouts(SOBJECT_SCOPE);
for(MetadataService.Metadata m : getService().readMetadata('Layout',layouts).getRecords()){
    layoutMetadata = (MetadataService.Layout) m;
    objectName = splitReturnFirst(layoutMetadata.fullName,'-');
    if(layoutMetadata.layoutSections != null) for(MetadataService.LayoutSection ls : layoutMetadata.layoutSections)
        if(ls.layoutColumns != null) for(MetadataService.LayoutColumn lc : ls.layoutColumns)
            if(lc.layoutItems != null) for(MetadataService.LayoutItem li : lc.layoutItems)
                if(String.isNotBlank(li.field)){
                    columns.clear();
                    columns.add(objectName);
                    columns.add(li.field);
                    columns.add(layoutMetadata.fullName);
                    columns.add(li.behavior);
                    rows.add('"'+String.join(columns,'","')+'"');
                }
}
rows.sort();
rows.add(0,'Object,Field,Layout,Behavior');
System.debug(String.join(rows,'\n'));

//================================================
// HELPER METHODS
//================================================
static MetadataService.MetadataPort getService(){
    MetadataService.MetadataPort service = new MetadataService.MetadataPort();
    service.SessionHeader = new MetadataService.SessionHeader_element();
    service.SessionHeader.sessionId = UserInfo.getSessionId();
    return service;
}

static String splitReturnFirst(String str, String separator){
    String returnValue = null;
    if(str != null){    
        List<String> split = str.split(separator,2);
        if(split != null && split.size() > 0){
            returnValue = split[0];
        }
    }
    return returnValue;
}

static Set<String> lowerCase(Set<String> s){
    Set<String> returnValue = null;
    if(s != null){  
        returnValue = new Set<String>();
        for(String str : s){
            if(str == null) returnValue.add(null);
            else returnValue.add(str.toLowerCase());
        }  
    }
    return returnValue;
}

static List<String> listLayouts(Set<String> scope){
    scope = lowerCase(scope);
    if(scope == null) scope = new Set<String>();
    final List<String> returnValue = new List<String>();
    final MetadataService.ListMetadataQuery q = new MetadataService.ListMetadataQuery();
    q.type_x = 'Layout';
    for(MetadataService.FileProperties layout : getService().listMetadata(
        new List<MetadataService.ListMetadataQuery>{q},25
    )){
        if(   scope != null 
           && scope.size() > 0 
           && !scope.contains(splitReturnFirst(layout.fullName,'-').toLowerCase())
        ){
            continue;
        }
        returnValue.add(layout.fullName.toLowerCase());
    }
    returnValue.sort();
    return returnValue;
}