  Localised transient EUV brightenings, sometimes named `campfires', occur
throughout the quiet-Sun. However, there are still many open questions about
such events, in particular regarding their temperature range and dynamics. In
this article, we aim to determine whether any transition region response can be
detected for small-scale EUV brightenings and, if so, to identify whether the
measured spectra correspond to any previously reported bursts in the transition
region, such as Explosive Events (EEs). EUV brightenings were detected in a
~29.4 minute dataset sampled by Solar Orbiter's Extreme Ultraviolet Imager on 8
March 2022 using an automated detection algorithm. Any potential transition
region response was inferred through analysis of imaging and spectral data
sampled through coordinated observations conducted by the Interface Region
Imaging Spectrograph (IRIS). EUV brightenings display a range of responses in
IRIS slit-jaw imager (SJI) data. Some events have clear signatures in the Mg II
and Si IV SJI filters, whilst others have no discernible counterpart. Both
extended and more complex EUV brightenings are found to, sometimes, have
responses in IRIS SJI data. Examples of EUI intensities peaking before, during,
and after their IRIS counterparts were found in lightcurves constructed
co-spatial to EUV brightenings. Importantly, therefore, it is likely that not
all EUV brightenings are driven in the same way, with some seemingly being
magnetic reconnection driven and others not. A single EUV brightening occurred
co-spatial to the IRIS slit, with its spectra matching the properties of EEs.
EUV brightenings is a term used to describe a range of small-scale event in the
solar corona. The physics responsible for all EUV brightenings is likely not
the same and, therefore, more research is required to assess their importance
towards global questions in the field, such as coronal heating.
