I couldn't get more info. Apparently this is another multi-entrance building, and I looked at the wrong / incomplete directory listing.

Moreover, those aren't "private info"; those eventually will be merged/uploaded into OSM in some form. uMap seem overkill.

Agreed in principle, but again, iD can't "write down" information, and I use iD.

I primarily (only) use iD.

This doesn't happen too often, so I think we good.

...that looks more like "mud water" than even sludge...

I do sometimes notice some OSM ways were drawn very horribly (e.g. one segment -> one OSM way when it would be better to combine/merge & extend, e.g. in your quoted Tai Po Tau case). Didn't notice who drew them in the first place.

a todo on the map; I will make a proper changeset later.

The only honourable defence I can give is that the guy mistook the smelly sludge as an actual wetland, but that's a really really low bar.

It seems to make sense to fully specify the (implicit) maxspeed for trunk roads / strategic routes. especially when there are already some maxspeed data along the way.

I might be beating a dead horse, but afaik a route should have a clear start/end point (and therefore clear concept of direction) while a network need not have direction.

In this case while the vibe is that the "thing" connects between Tsuen Wan station and TWW station, the exact start/end points are unclear, and the "things" itself branches off to different places, which means this "thing" cannot be a route. It therefore has to be a network.

Correct, but rumors have/had it that the villagers tried to "secretly" fill them up to consolidate the land so to go for some giant integrated (residential) development. In this context, converting them into dozens of independent `landuse=greenfield` makes no sense.

I get what you are trying to say, but the address says "ground floor", which implies the first floor (or more).

From experience this is usually the public servant dentistry (I omit them), or some sort of other "minor" clinics which share the same building.

I may have misunderstood something, but that's supposed to be the perimeter wall of the building.

Earlier typed wrong.

Man Nin Street obviously not `oneway=no`. Fixed with changeset.

It's obviously not `oneway=yes`. Fixed with changeset/176469866 .

Then, at least previous changes should somehow indicate "embankment=yes", the tag which did not exist.

From aerial images this looks like a bridge to me.

imo/afaik `area:highway` doesn't feel useful

Improved with changeset/176203026

I scrolled to the "ground floor" table and then thought there's nothing more...

See note note/5099138 ;

Now that Route 6 is open (at least for this area), what is the status of those seemingly duplicate sliproads? Probably `was:highway=*` rather than `highway=construction`?

Agreed in principle, but it seems "multi-level mapping" is undocumented in the OSM wiki, and I shall remain defensive on this.