maybe ref=* would fit?

Hello! node/4714732031/history has id = 18 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/4162090969/history has id = 35 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/12762306027/history has id = 00 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/13296855885/history has id = U57616487 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/11200336426/history has id = VDE 2093 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/13206281162/history has id = 101 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/11155892881/history has id = node/9589820224 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/8242788698/history has id = 1 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/8600376810/history has id = 1404546 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/10144425285/history has id = 22 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/12495452088/history has id = P56E that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

maybe shop = group_of_vending_machines to make clear it is not selling vending machines themselves?

See also changeset/162500409 where I had a similar discussion with someone else

Hello! node/11649450097/history has id = QST-006A that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/11054994992/history has id = vhm 162 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/8872749206/history has id = 19 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/11902060487/history has id = 136520 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/12087642726/history has id = s2r2ogJsDSLohPw6dcbgRgyrcuk= that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/11303825851/history has id = 665470028 that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?

Hello! node/7147568387/history has id = unicef_eco_plast that was added in this edit
What is the meaning of this unusual key? Is this tag needed?
Or maybe can it be expressed in a more typical way that would be easier to understand?
Or maybe this key can and should be documented as useful tagging schema?