How to reproduce:
1. Open the "WebGL_Colorspace" project
2. Open the "SampleScene"
3. Switch build to "WebGL" (File > Build Settings)
4. Build And Run
5. In Player open the browser’s console
6. While resizing Player, observe the viewport and browser console

Expected result: viewport resizes without any visual glitches and no warnings are logged in the browser console
Actual result: viewport flickers when it is resized and the browser console logs warnings

Reproduced with: 2020.3.46f1, 2021.3.21f1, 2022.2.12f1, 2023.1.0b9, 2023.2.0a7

Reproduced on: Windows 10 (by reporter), Windows 11

Warnings (Firefox Console):
1. Performance Warning: Recreating Offscreen FBO (1339x701 => 1314x688) Build.framework.js.gz:2:44333
2. Performance Warning: Recreating Offscreen FBO (1314x688 => 1277x666) Build.framework.js.gz:2:44333
3. Performance Warning: Recreating Offscreen FBO (1277x666 => 1257x652) Build.framework.js.gz:2:44333

Notes:
1. The browser’s console can be opened by different shortcuts. These shortcuts are also different for each browser. The default shortcuts can be located here https://docs.unity3d.com/Manual/webgl-debugging.html
2. Not reproducible when “Gamma” Color Space is used in WebGL Player (Edit > Project Settings > Player > Other Settings)
3. Reproducible when using the custom "Responsive" WebGL Template (Edit > Project Settings > Player > Resolution and Presentation)