Open Chrome app in your mobile phone and tap on 3-dots menu and select Settings option.
It'll open Chrome Settings page.
Scroll down to bottom and under "Advanced" section, tap on About Chrome option.
Tap on "Application version" 7 times to enable developer mode.
There is no "Advanced" in the menu, but I found the version under "Google Chrome" and tapped on it and saw "copied" 7 times, and then nothing happened.
EDIT: After making an error happen, I did start seeing log info in 'chrome://inspect'. I am not sure the Advanced/tapping is even necessary.
Instructions as of February 2021:
Open Chrome app in your mobile phone and tap on 3-dots menu and select Settings option.
It'll open Chrome Settings page.
Scroll down to bottom and under "Advanced" section, tap on About Chrome option.
Tap on "Application version" 7 times to enable developer mode.
It's only April but something must have changed.
There is no "Advanced" in the menu, but I found the version under "Google Chrome" and tapped on it and saw "copied" 7 times, and then nothing happened.
EDIT: After making an error happen, I did start seeing log info in 'chrome://inspect'. I am not sure the Advanced/tapping is even necessary.
This worked for me Feb 22.
And after that? How do you open the developer tools. I can't find it anywhere.