Dedicated Trigger Developer Guide's Trigger EDM section

Dedicated trigger EDM section covering:

    EDM targets
        Note on AODSLIM: Further reductions
    Optional EDM details
        InViews
        allowTruncation
        Aliases
    unit tests
    EDM manipulation
    Procedure for modifying trigger EDM
        Adding content
        Removing content
    Test and validate
        Useful trigger tests
        Tips on running own trigger tests
        Cross-check: Container recording
        Cross-check: Container content
        Estimate size increase

docs/athena/trigger/developers/algos.md

@@ -44,18 +44,16 @@ ready) [fast e/gamma cluster maker algorithm]({{data.athena_git_url}}/blob/{{dat
 
 
 ## Saving EDM objects
-If the reconstructed objects that are created by algorithms
-need to be recorded in the output file these steps should be followed:
+The following software modifications are needed to record reconstructed objects created by HLT algorithms to file:
 
-1. contact trigger EDM coordinator [found on trigger Core s/w twiki](https://twiki.cern.ch/twiki/bin/view/Atlas/TriggerCoreSoftware)
 1. in the python configuration of the algorithm an instance of the
-  `recordable` function from [TrigEDMConfig.TriggerEDMRun3]({{data.athena_git_url}}/blob/{{data.branchTier0Short}}/Trigger/TriggerCommon/TrigEDMConfig/python/TriggerEDMRun.py#L34) needs
+  `recordable` function from [TrigEDMConfig.TriggerEDM]({{data.athena_git_url}}/blob/{{data.branchTier0Short}}/Trigger/TriggerCommon/TrigEDMConfig/python/TriggerEDM.py#L34) needs
   to be used when setting the name of the collection. It assures that
-  the naming convention of the HLT EDM is followed and no trivial typos sneak in between name of the container .
-1. The collection (type and name)  has to be listed in 
-  [TrigEDMConfig.TriggerEDMRun3]({{data.athena_git_url}}/blob/{{data.branchTier0Short}}/Trigger/TriggerCommon/TrigEDMConfig/python/TriggerEDMRun3.py)
+  the naming convention of the HLT EDM is followed and no trivial typos sneak in.
+1. The collection (type and name)  has to be listed in
+  [TrigEDMConfig.TriggerEDMRun3]({{data.athena_git_url}}/blob/{{data.branchTier0Short}}/Trigger/TriggerCommon/TrigEDMConfig/python/TriggerEDMRun3.py) (or `TriggerEDMRun4` for upgrade studies)
   together with the required output file types in which it should be recorded. Typically the object should be stored
-  at least in `BS`, `ESD` and `AOD`. Consult the Trigger EDM coordinator about this. Especially about the `AOD` formats where the size is constrained.
+  at least in `BS` and `ESD` (`RDO_TRIG` files - the equivalent of "raw" files for MC - contain all `ESD`-labelled content).
 1. Ensure that in
   [HLTEDMCreator.h]({{data.athena_git_url}}/blob/{{data.branchTier0Short}}/Trigger/TrigSteer/TrigOutputHandling/src/HLTEDMCreator.h)
   and
@@ -69,7 +67,9 @@ need to be recorded in the output file these steps should be followed:
 Once the above steps are done the object should appear in the relevant output files.
 For POOL files (ESD, AOD) the content can be checked with one of the following scripts:
 `checkxAOD.py filename` `checkSG.py filename` `checkFile.py filename`.
-  
+
+See the [trigger EDM guidelines](edm.md#procedure-for-modifying-trigger-edm) on the full procedure for adding new trigger EDM content (testing, verification and approval).
+
 
 ## Troubleshooting
 Typically a reconstruction algorithm uses many input data