That report simply lists all assets which are not Windows assets. If you would like to exclude Location assets, you might edit the report and replace the SQL code with the following:
Select Top 1000000 tsysAssetTypes.AssetTypeIcon10 As icon,
tblAssets.AssetName,
tblAssetCustom.Model,
tblAssetCustom.Manufacturer,
tblAssetCustom.Location,
tblAssets.IPAddress,
tblAssets.Lastseen,
tblAssetCustom.AssetID
From tblAssetCustom
Inner Join tblAssets On tblAssetCustom.AssetID = tblAssets.AssetID
Inner Join tsysAssetTypes On tblAssets.Assettype = tsysAssetTypes.AssetType
Where tblAssets.Lastseen < GetDate() - 30 And tblAssetCustom.State = 1
And tsysAssetTypes.AssetTypename Not In ('Windows', 'Location')
Order By tblAssets.AssetName