
This post lists the table of contents and the document links in the "Release Notes" doc listed at [link] a.k.a. the Vivado Design Suite User Guide, Release Notes, Installation, and Licensing, UG973 (v2018.2) July 23, 2018.
This post is useful if you've tried to find where the "root" Vivado doc is on the "Documentation" tab at [link], what's included in the doc and the major Vivado docs referenced from it.
Document Location

Table of Contents
Chapter 1: Release Notes 2018.2
What’s New 5
Important Information 8
Known Issues 10
Chapter 2: Architecture Support and Requirements
Operating Systems 11
Architectures 12
Compatible Third-Party Tools 13
System Requirements 14
Chapter 3: Download and Installation
Downloading the Vivado Design Suite Tools 16
Download Verification 17
Installing the Vivado Design Suite Tools 24
Installing Cable Drivers 30
Installing Windows Driver 30
Uninstalling Cable Drivers 30
Installing Linux Driver 30
Uninstalling Linux Driver 31
Adding Additional Tools and Devices 31
Network Installations 32
Batch Mode Installation Flow 34
Obtaining Quarterly Releases 37
Uninstalling the Vivado Design Suite Tool 38
Checking Required Libraries 39
Chapter 4: WebTalk
WebTalk Participation 40
Setting WebTalk Install Preference 41
Setting WebTalk User Preferences 42
Checking WebTalk Install and User Preferences 43
Types of Data Collected 43
Transmission of Data 44
Chapter 5: Obtaining and Managing a License
Licensing Overview 45
Generating/Installing Certificate-Based Licenses 46
Managing Licenses On Your Machine 52
Using the Xilinx Product Licensing Site 54
Chapter 6: Older Release Notes
Release Notes 2018.1 67
Important Information 76
Known Issues 78
Appendix A: Additional Resources and Legal Notices
Xilinx Resources 79
Solution Centers 79
Documentation Navigator and Design Hubs 79
Licenses and End User License Agreements 80
Registered Guest Resources 80
References 80
Training Resources 81
Please Read: Important Legal Notices 81
References
1. UltraFast Design Methodology Guide for the Vivado Design Suite (UG949)
2. UltraFast™ High-Level Productivity Design Methodology Guide (UG1197)
3. UltraFast Embedded Design Methodology Guide (UG1046)
4. Vivado Design Suite User Guide: Logic Simulation (UG900)
5. Vivado Design Suite User Guide: High-Level Synthesis (UG902)
6. Vivado Design Suite User Guide: Partial Reconfiguration (UG909)
7. Vivado Design Suite Tutorial: Partial Reconfiguration (UG947)
8. Vivado Design Suite User Guide: Hierarchical Design (UG905)
9. Vivado Design Suite User Guide: Model-Based DSP Design Using System Generator
(UG897)
10. Vivado Design Suite User Guide: Implementation (UG904)
11. Vivado Design Suite User Guide: Power Analysis and Optimization (UG907)
12. IP Release Notes Guide (XTP025)
13. Platform Cable USB II Data Sheet (DS593)
14. Parallel Cable IV Data Sheet (DS097)
19. PS and PL-Based 1G/10G Ethernet Solution (XAPP1305)
20. Secure Boot of Zynq-7000 SoC (XAPP1175)
21. Model Composer User Guide (UG1262)
22. PetaLinux Tools Documentation: Reference Guide (UG1144)
Reference
Xilinx logo found via https://twitter.com/xilinxinc at [link]
Critique
This is what I see when I click on the Documentation tab:

This says that the _most_ important doc is UG1118 - Vivado Design Suite User Guide: Creating and Packaging Customer IP (ver2018.2) along with guides on which edition I should use, 2 methodology guides and a marketing piece. These _are_ useful docs... once I know how to install and run Vivado. I would suggest the first doc listed be: Getting Started with Vivado covering these points.