TL;DR:

We revamped and "nuked" the IL leaderboards, and you can view the archived runs here: https://docs.google.com/spreadsheets/d/e/2PACX-1vRMIeFLrTvqOv2gURihDPoPVVnOgEYzLylO6KRG-S_FP7JcNw4jm7oG8EW_0g-37PTvzrQI0VDBL-u9/pubhtml

Summary

About a month ago, the IL leaderboards received a major overhaul. You can view the new setup here: https://www.speedrun.com/tr4/levels

Previously, the ILs were rather formless because they tried to be Individual Levels, which doesn't work for a non-linear game like Tomb Raider IV where many levels are revisited and/or interconnected.

This new implementation was a collaborative effort by the moderation team which spanned at least a month's worth of time, with multiple drafts and lengthy detailed discussions.

What are the changes?

• No more weird IGT -- RTA is the way!
• Clear and concise definitions of level Entrance, Exit, and other requirements in each IL's rules!
• This includes complete support for Collectibles Categories! (Secrets%, Max%)
• Instead of being strictly Individual Levels, some ILs combine multiple in-game levels as Interconnected Levels and feature some (imo) cool names!
• The IL leaderboard simplifies to only Glitched and Glitchless -- no "Restricted" Glitched variants.

What about old runs?

• The changes required us to effectively "nuke" the entire existing IL leaderboard, with the exception of The Times Exclusive level/game.
• The old runs were archived, so they aren't totally lost. They rarely aligned with the old rules and definitely not with the overhauled rules, so we started anew!