Drain pipe/ Sewer clean out

[Question12345]

Hi, can anyone tell us what this pipe may be. Old 1904 home. Lived here 4 years no issues.
we did some gardening Dec last year at the front of our house and noticed a concrete slap coveting a pipe underground.
I noticed a build up of was accumulating on our flower bed and it was coming from this pipe. We lifted it and a small amount of water came gushing out, it looks like clean water or rain water, no foul smell no sewage. We do not have a blocked sink a or toilets. And it was only that one gush, no more water since, it contain for a week on and off recently. I would really appreciate if some might know what this is. Could it be an unused pipe or old footing for washing line? All suggestions welcome.

Is it metal? In any case would imagine it's some kind of old post type thing. Probably has loads of concrete around it below the soil level hence any build up of water if it rains a lot due to lack of drainage where concrete is. Doesn't look anything to worry about. You could try digging around it if curious. Alternatively someone may at some point had a downpipe going there from a shed or something into a small soakaway.