You'll never find evidince hard enough to fashion the sort of club people who ask such questions ought to be bludgeoned with.
Do you really think anyone would be so stupid as to leave hard evidince? That's the magic of the whole process, they can do those things fully within the bounds of the process. They decide (or don't), often at the urging of lobbyists, or non-lobbyists parties who themselves typically aren't completely impartial, what they want. And often they have a specific product in mind that they want, but they can't say that so they write the requirement to all but say it.
Often times this is very reasonable and comes as the result of the end user having used multiple products or having used multiple contractors and knowing from experience with near certainty what or who they want.
In the alternate case where it's pork, this is often how upstarts get their start. Whoever the prime is doesn't wanna pay out the ass for someone else's pork that's been inserted into the requirements so connections get leveraged and several dominoes later a subcontractor to someone is under contract + NDA to buy a controlling stake in an idling paper mill and refit as necessary the small town's wastewater plant it dumps into because that is how they are going to provide the filter media meeting the performance specified in the requirements without being forced to pay out the ass for the product the lobbyists ghost wrote into it. The prime has basically entered into contract to create a company making a competing product out of thin air. There are many funny stories like this kicking around the beltway.
Do you really think anyone would be so stupid as to leave hard evidince? That's the magic of the whole process, they can do those things fully within the bounds of the process. They decide (or don't), often at the urging of lobbyists, or non-lobbyists parties who themselves typically aren't completely impartial, what they want. And often they have a specific product in mind that they want, but they can't say that so they write the requirement to all but say it.
Often times this is very reasonable and comes as the result of the end user having used multiple products or having used multiple contractors and knowing from experience with near certainty what or who they want.
In the alternate case where it's pork, this is often how upstarts get their start. Whoever the prime is doesn't wanna pay out the ass for someone else's pork that's been inserted into the requirements so connections get leveraged and several dominoes later a subcontractor to someone is under contract + NDA to buy a controlling stake in an idling paper mill and refit as necessary the small town's wastewater plant it dumps into because that is how they are going to provide the filter media meeting the performance specified in the requirements without being forced to pay out the ass for the product the lobbyists ghost wrote into it. The prime has basically entered into contract to create a company making a competing product out of thin air. There are many funny stories like this kicking around the beltway.