This element is an imitation of MacOS 'STR#' resources. It has an attribute of "index", which has a numerical value corresponding to the original resource ID:
This element contains child elements with form <string>, which have an attribute of "index", and contents of whatever the string is supposed to be. The index is zero-based, unlike the original STR# resources, whose indices are one-based. For example, the filenames are specified in this fashion:
128: Errors
129: Filenames
130: Top-Level Interface Items
131: Prompts
132: Network Errors
133: Key Codes to Names
134: Preferences Advice
135: Computer Interface
136: Join Dialog Messages
137: Weapon Names
138: File Search Path
139: Preferences Groupings
140: Postgame Network Game Statistics
141: Net Game Setup
142: New Join Dialog Messages
143: Progress Strings for Networking
150: Item Names
151: Item types
153: Net Statistics Strings
200: OpenGL-Option Color-Picker Prompts
<!-- STR# Resource: "Filenames" -->
<stringset index="129">
<string index="0">Shapes</string>
<string index="1">Shapes.16</string>
<string index="2">Sounds</string>
<string index="3">Sounds.16</string>
<string index="4">Aleph One Preferences</string>
<string index="5">Map</string>
<string index="6">Untitled Game</string>
<string index="7">Marathon</string>
<string index="8">Aleph One Recording</string>
<string index="9">Physics Model</string>
<string index="10">Music</string>
<string index="11">Images</string>
<string index="12">Movie</string>
</stringset>