Documentation about DFR0528

Hello!

Yesterday I received this DFR0528 Raspberry Pi UPS.

So, I don't understand this device complete.
Where I can find a documentation beside this:
https://wiki.dfrobot.com/UPS%20HAT%20fo ... 8#target_3

To understand it I need a block diagram, schematic, Pin assignment.
Does it has an steip regulator?
What is the charging current?

I have an problem regarding I2C:
I enabled I2C and install the package.

[email protected]:~ $ sudo i2cdetect -y l
Error: I2C bus name doesn't match any bus present!
Usage: i2cdetect [-y] [-a] [-q|-r] I2CBUS [FIRST LAST]
i2cdetect -F I2CBUS
i2cdetect -l
I2CBUS is an integer or an I2C bus name
If provided, FIRST and LAST limit the probing range.
[email protected]:~ $

Which component limits the current?
I want to use it on a Raspberry Pi4


Thank you.