This isn't directly related per se, but if you're doing "what-if" stuff then it's nice to be able to switch between human-readable and math-friendly versions of dates. The following commands will print a specific date in your system's default display format (e.g. in your local time zone); the first one uses a human-readable format as input, and the second one uses an epoch timestamp as input.
date --date '2020-09-02 10:00:01 UTC'
date --date '@1599040801'
You can also give both parameters, to print a specific date in a specific format. For instance, see how these commands let you conver a specific point in time between formats; I've added extra spaces to line things up to make it more obvious what's going on, but they're not required (for more information on the date command's syntax, see the date(1) man page.
date --date '2020-09-02 10:00:01 UTC' '+%s'
date --date '@1599040801' '+%Y-%m-%d %H:%M:%S %Z'
date --utc --date '@1599040801' '+%Y-%m-%d %H:%M:%S %Z'
If this project ever somehow becomes a Big Thing(tm), I'll turn this into a proper data source and have the Web content generated from it, rather than maintaining it by hand; for now, though, here's machine-parseable versions of the base data that you need to generate your own version of this page:
[
{ "item": "Duke Nukem Forever", "estimate": 907243199, "release": 1307613600 },
{ "item": "Half-Life 2: Episode 3", "estimate": 1198670399, "release": null }
]
---
- name: "Duke Nukem Forever"
estimate: 907243199
release: 1307613600
- name: "Half-Life 2: Episode 3"
estimate: 1198670399
release: null
...