SELECT `database`, COUNT(*) as hitcount FROM event.mediawiki_api_request WHERE year = 2020 AND month = 6 AND day = 14 and params['action'] = 'query' and params['prop'] = 'pageterms' group by `database`;
database	hitcount
ukwiki	1
ptwiki	482
rowiki	13
trwikinews	2
wikidatawiki	338
nlwiki	2
fawiki	45
svwiki	9
cswiki	2
zhwiki	10
plwiki	34
enwiki	927
ruwiki	120
eswiki	243
jawiki	19
frwiki	188
dewiki	62
arwiki	33
itwiki	67

Paramaters sent to cases of wikidatawiki requests can be found in P11653 (Includes private data, protected for view but you should have access)

See also T255949...

I thought about this some more. We have basically 4 cases I can see:

1. WP article is connected to a WD Item. We call the API on the WP article. We get back the data for the WD Item. ✅
2. WD non-Item page is connected to a WD Item. We call the API on the WD non-Item page. We get back the data for the WD Item. ✅
3. WD Item is connected to another WD Item. We call the API on the first. What should we get back? 🚫
4. WD Item exists and we call the API directly on it, not through its sitelink connection. What should we get back? 🚫

3 is an outlier we declare to be handled like 1 and 2. 1 and 2 are what we intended it for. I fear people are using it for 4. Can we confirm this by looking at some sample calls for the API? If that assumption is correct can we deprecate that usage and point people at an alternative?

Anything I'm missing?

In T256255#6279718, @Lydia_Pintscher wrote:

3 is an outlier we declare to be handled like 1 and 2. 1 and 2 are what we intended it for. I fear people are using it for 4. Can we confirm this by looking at some sample calls for the API?

The sample of calls in wikidatawiki can be found in here (let me know if you need access):
{P11653}